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Biological Survey of Ironwood Forest National Monument

APPENDIX 1 - Listing of Township-Range locations of soils examined for this study, including 7.5' quadrangle names, and elevations in feet above sea level (taken from topographic maps).

(The listings are read as in the following example of the first listing, where the soil site examined lies in the northeast quarter of the northeast quarter of section 19, Township 11 south, Range 10 east, located on the 'West of Marana' 7.5 minute topographic map, at an elevation of 1935 feet.) (BM = USGS benchmark location with elevation, noted on the topographic maps, as location references. Location designations such as NNW (= north-northwest) and center SW4 (geometrical center of southwest quarter) follow standard surveying procedures) (asl = feet above sea level). The elevation designations given here were read off the topographic maps (not from portable GPS units), and so are useful in recreating the sample locations on the maps. The site number given on the geology map and referred to in the text is given first on this list (S1, etc), and the next number (1-04) is a field number.


S1. 1-04 NE4 NE4 19, 11S, 10E, 1935', West of Marana, 1935'

S2. 2-04 NE4 NE4 25, 11S, 9E, Silver Bell East, 2000'

S3. 3-04 near center NW4 26, 11S, 9E Silver Bell East, in banks of major wash, 2080'

S4. 4-04 NW4 SE4 23, 11S, 9E, Silver Bell East, 2040'

S5. 5-04 SE4 SE4 11, 11S, 9E, Silver Bell East, 1960'

S6. 6-04 NW4 NE4 1, 11S, 9E, Samaniego Hills, 1865'

S7. 7-04 NW4 SW4 2, 11S, 9E, Silver Bell East, 1935'

S8. 8-04 NW4 SE4 15, 11S, 9E, Silver Bell East, 2065'

S9. 9-04 SW4 SW4 15, 11S, 9E, Silver Bell East, 2100'

S10. 10-04 SE4 SE4 20, 11S, 9E, Silver Bell East, 2200'

S11. 1-06 NE4 NE4 29, 12S, 9E, Waterman Peak, 2300'

S12. 2-06 near center of northern half, sec 5, 13S, 9E, Waterman Peak, 2345'

S13. 3-06 east central part SE4, sec 5, 13S, 9E, Waterman Peak, 2305'

S14. 4-06 NE4 NW4 5, 13S, 9E (200 ft east of BM 2316) Waterman Peak, 2315'

S15. 5-06 about 200 ft SSW from last sample, elev 2320' (NE4 NW4 5, 13S, 9E)

S16. 6-06 at the center of the northern edge NE4 18, 13S, 9E, Waterman Peak, 2305'

S17. 7-06 center of west edge of W half, sec 4, 13S, 9E, Waterman Peak, 2300'

S18. 8-06 SE4 SE4 33, 12S, 9E, Waterman Peak, 2245'

S19. 9-06 SW4 SW4 22, 12S, 9E, Waterman Peak, 2220'

S20. 1-18 NE4 SE4 33, 12S, 9E, Waterman Peak, 2245'

S21. 2-18 SW4 SE4 34, 12S, 9E, Waterman Peak, 2250' (200 ft south of AZ Game & Fish developed water)

S22. 3-18 NNW flank of hill 2512T centered in SW quarter sec 34, 12S, 9E, Waterman Peak, 2300'

S23. 4-18 three samples on north flank of hill 2704T whose top is in W half sec 35, 12S, 9E, Waterman Peak. All samples in NE4 NE4 34, 12S, 9E, elevations near 2200', 2240' and 2250'.

S24. 5-18 near center SW4 26, 12S, 9E, Waterman Peak, 2160'

S25. 6-18 near center of E half 25, 12S, 9E, Waterman Peak, 2090'

S26. 1-31 SE4 SE4 9, 12S, 8E, Silver Bell West, 2600'

S27. 2-31 near SE corner 18, 11S, 8E, Silver Bell West, 2100'

S28. 3-31 NE4 NE4 13, 11S, 7E, Silver Bell West, 1960'

S29. 4-31 south central part SW4 11, 11S, 7E, Silver Bell West, 1870'

S30. 5-31 NW4 NW4 2, 11S, 7E, Friendly Corners, 1780'

S31. 6-31 center of north edge of NW4, sec 4, 11S, 7E, Greene Reservoir, 1870'

S32. 7-31 near center SW4 8, 11S, 7E, Gap Tank, 1930'

S33. 8-31 NW4 NW4 20, 11S, 7E, Gap Tank, 1855'

S34. 1-31 M - NE4 NE4 2, 14S, 10E, Cocoraque Butte 7.5, 2220'

S35. 2-31 M - 10 m north of BM 2219, north central part Sec 2, 14S, 10E, Cocoraque Butte 7.5, 2215'


S36. 3-31 M - 50 m south of BM 2246, NE4 SE4 4, 14S, 10E, Cocoraque Butte 7.5, 2250'

S37. 4-31 M - SW4 SW4 4, 14S, 10E, Cocoraque Butte 7.5, 2270'

S38. 5-31 M - NW4 NW4 35, 13S, 9E, Waterman Peak 7.5, 2270'

S39. 1-10 Apr - near center SW4 33, 11S, 7E, Gap Tank, 1950'

S40. 2-10 Apr - NW4 NW4 24, 11S, 6E, Gap Tank, 1760', about 50 m south of road.

S41. 3-10 Apr - NW4 NW4 5, 12S, 6E, Santa Rosa Mts NE, 1755', 10 m west of road.

S42. 4-10 Apr - near center SW4 8, 12S, 6E, Santa Rosa Mts NE, 1793', 10 m west of road.

S43. 5-10 Apr - SW4 SW4 17, 12S, 6E, Santa Rosa Mts NE, 1815', 100 m west of road and visita

S44. 6 & 7-10 Apr - southern half SW4 5, 12S, 6E, west of road, Santa Rosa Mts NE, 1775'

S45. 8-10 Apr - far NW4 NW4 6, 12S, 6E, about 100 m south of road, Santa Rosa Mts NE, 1765'

S46. 9-10 Apr - N half NW4 6, 12S, 6E, Santa Rosa Mts NE, 1770'

S47 11 May-01 -near center N half NW4 19, 11S, 7E, Gap Tank, 1810'

S48 11 May-02 - SW4 22, 11S, 7E, Gap Tank, 1970-1990'

S49 23 May-01 - center of S half NW4, 9, 10S, 6E, Silver Reef Mts SE, 1630' (sand dune)

S50 23 May-02 - 0.1 mile due west of center sec 30, 9S, 6E, Silver Reef Mts SE, 1670'


M = meters, ft = feet, cal is amount of calcareous (calcite) reaction to one molar HCl acid - non = none, mod = moderate, vig is vigorous or strong. Calcrete essentially is caliche. Dia = diameter of pebbles or rocks. All soil colors are from the Munsell color chip book. All designation (like 'S1') are plotted on a map on the CD Rom.

S1. 1-04 - Near edge of floodplain, near Silverbell Rd. First terrace begins 100 m to the west

0-36 cm - very fine sand to silt loam, 10 YR 6/6, non-calc.

36-52 cm - sandy sl pebbley loam, color 5 YR 6/3 to 7.5 YR 6/4 dry (7.5 YR 4/6 moist)

52-97 cm - more rocks, pebbles, to 3 cm dia. A coarse sandy loam. Color near bottom 5 YR 5/4. Very loose unstructured soil throughout profile. Calc reaction in lower half, and pebbles coated with caliche on undersides in bottom 20 cm.

Veg: not noted - thick with mesquite.

S2. 2-04 - Creosote flat west along Silverbell Rd, moderate desert pavement, rocks 3-15 cm dia.

0-28 cm - silty clay loam (good ribbon), Color dry 2.5 YR 4/4 to 5 YR 4/6. Non-calc. Abrupt contact with caliche horizon below. Many plant roots noted in this layer, very few below 30 cm.

28-67 cm - caliche stringers in a pinkish hard very calc loam. Entine layer very calcareous. (Caliche color 2.5 YR 6/4 dry, soil is 2.5 YR 5/4 dry. Fine subangular blocky structure. Cannot penetrate below 67 cm - caliche.

Veg: creosote, scattered palo verde, ironwood in washes, rare saguaro.

S3. 3-04 - note at major wash with 3 + meters of downcutting - exposed here is a typical recent alluvium which is becoming calichified. Pebbly sand loam shows laminar bedding, with pink to red-brown colors, containing abundant lenses of heavily calichified alluvium, which id quite hard. Present are calichified vertical root molds, and pods of pure white caliche.

S4. 4-04 - on bajada slope, very shallow rills here. More complete desert pavement , 4-15 cm dia, black tops and red bottoms on rocks.

•  cm - loose silt to silt loam, possibly eolian, dry color 7.5 YR 5/6.

3-22 cm - sandy clay loam, non-calc, dry color 2.5 YR 4/6 or 4/8.

22-28 cm - top of pink caliche layer with many hard nodules in a matrix of loose sandy loam, very calc.

S5. 5-04 - near check dam.

Top 25 + cm is loose very calc silt to sandy silt (eolian?), 7.5 YR 5/6 dry. In a rill is exposed 35 + cm of red-brown sandy loam with lenses of hard caliche, just as noted at stop 3-04 above. As there is no reddish 'B' clay-rich zone above the calcrete, this situation is probably polygenetic, with old 'B' eroded off the surface before addition of eolian surface layer.

Veg: creosote dominant.

S6. 6-04 - stratigraphy exposed on 2 meter-deep west cut of a shallow sand/gravel borrow pit, near Pinal Air Park. Agricultural fields not far east of here before the air field.

0-52 cm - silt loam (no ribbon when wet), close to 50% pea gravel, color 5 YR 6/3 dry., mod calc.

52-74 cm - sandy clay loam to clay loam, more red-brown color ( 5 YR 5/6 dry), with common caliche nodules and calcareous reaction.

74-127 cm - light colored calichified pebbly sandy loam, 5 YR 7/3 dry color.

Veg: creosote, palo verde, some mesquite, bursage, rare saguaro.

S7. 7-04 - flat interfluve, nearest wash 30 m on either side of sample point. A surface lag present, rocks 2-15 cm dia, slight lichen coatings. Some rocks with red undercoats, some larger ones with caliche undercoats, some rocks overturned, as is the usual case.

•  cm - loose silt, light color, 2.5 YR 4/6 dry, non calc.

1-4 cm - pebbly silty clay loam, vertical clay coatings noted, sub angular blocky structure.

4-38 cm - sandy clay loam, with pea gravel, few pebbles. Color 5 YR 5/4 dry, sl calc.

Veg: creosote, scattered palo verde, rare saguaro. No bursage.

S8. 8-04 - on flats, 30 m east of a riparian zone. Scattered lag on surface, 3-10 cm dia, some rocks red undercoatings.

•  cm - olive colored loose very pebbly silty loam, 5 YR 5/4 dry. Non-calc.

3-20 cm - very pebbly clay loam, 2.5 YR 4/8 dry, non to slight calc.

20-42 cm - progressively more pink color, tending to a pebbly clay loam, 2.5 YR 5/6 dry (4/6 moist), slight to mod calc, becoming vigorous calc reaction below 39 cm.

Veg: Creosote-bursage, with dead staghorn cholla and dry christmas cactus on flats; Palo verde, ironwood, saguaro along riparian zones.

S9. 9-04 - in a high topographic saddle (drainage divide) in southern Samaniego Hills.

Uniform soil 0-77 cm depth - color 7.5 YR 5/8 dry, very calc to total depth. Colors near to the bottom of the hole near 5 YR 5/4 dry. Pebbles pea size to 3 cm dia, about 10% of bulk throughout the depth. Texture a loose silt loam, damp only 10-20 cm depth, dry in rest of hole. With good potential for breezes here, eolian and sheetflood effects prevent real soil development.

Veg: good diversity - creosote, bursage, barrel and teddy bear cactus, staghorn cholla, Christmas cactus, prickly pears on north-facing slopes and flats, rare ironwoods, some mammilaria. No ocotillo. Saguaros concentrated on south-facing hillslopes.

S10. 10-04 - at the granite quarry. At the surface is a eroded, residual 'B' horizon, a rocky red clay loam, non-calc, about 40 cm thick, underlain by a variably thick caliche. Across a wash to the south (along side road entering the quarry) is a gray-brown colored fluvial deposit overlying the relict 'B', assuredly a Holocene alluvium coating the granite pediment which crosses the valley here.

Veg: palo verde, ironwood, saguaro, creosote, bursage, staghorn cholla.

S11. 1-06 (6 Feb 03) In a roadcut along access road to Waterman Mts from Avra Valley Rd. Near a east-flowing wash with 4+m of relief. Elev 2300 ft.

0-40 cm: v rocky v calc sandy loam. Rocks 2-6 cm dia. 5YR 6/4 dry.

40-128 cm: v calc loam to silt loam. No obvious B buildup. Calcite thin fillings on fractured ped surfaces, but no obvious white streaks. 5YR 6/4 dry.

128-258 cm: similar to above, but with common rounded caliche nodules and vertical columns present, general lighter color - 5YR 7/3.

Veg: creosote, bursage, prickly pear, PV, few ironwoods along washes. Catclaw acacia, staghorn cholla, Christmas cactus.

S12. 2-06 Flats, cut by shallow rills. Elev 2340 ft. Surface lag is pebbles and pea gravel, 1-4 cm dias.

0-66 cm: td, rock on bottom. No layering noted. V calc to td. Color 10 YR 6/4 to 6/6 dry. Loose silt loam, inc rocky in lower half, rocks 1-3 cm dia, rounded to sub ang.

Veg: creosote, bursage, common ocotillo, teddy bear, PV, scat saguaros, few ironwood along washes.

S13. 3-06 note only: Elev. 2300 ft. red color desert pavement and some varnishing - developed upon a low residual outcrop of Cretaceous sandstone and limestone, containing a black limestone layer which is a coquina with abundant broken pelecypod fossils, very much like seen in Yetman saddle, south from parking lot west of Gates Pass, Tucson Mts. Limestones much like these contain rare teliost fresh water fish fossils near Veasy Elementary school, south of Ajo Road in the southern Tucson Mountains. A black varnish washing away, and some rocks with strong clear varnish. Slight reddening on bottom of some rocks.

S14. 4-06 Along narrow and little used 4X4 road westward towards Waterman Pass and the T.O. Reservation. Elev. 2320 ft. Uniform sandy-silty loam. Color 5 YR 5/6 dry, td 74 cm, sl rocky to td. Loose, no structure except with top 5 cm or so, some SA blocky. Top 10 cm non-calc, calc increases below 20 cm to td.

Veg: creosote, prickly pear, teddy bear, barrel cactus, scattered saguaros and bursage.

S15. 5-06 Nearby but uphill to 4-06, near toe slope of hills to the south, located just into PV stand. Note big change of vegetation relative to 4-06. About 10 ft higher elev than 4-06. Very rocky (>75% rocks) sandy loam, darker color but lacking high clay. Color 5 YR 5/6, non calc. Dug only 25 cm. The very rocky soil on the slope grades quickly downslope to a loamy soil that supports creosote.

Veg: palo verde- bursage dominant. Bursage extends as a dense cover along a narrow zone below the PV on hillslope, where creosote does not live.

S16. 6-06 In flats downvalley, surface lag is pebbles composed of red Jurassic sandstone. Td about 35 cm, very rocky below that. Loose silt loam soil. Color 5 YR 5/4, fairly calc throughout the interval.

Veg: creosote, scat mesquite, prickly pear is common, scat saguaros. Nearby note two red-purple Santa Rita Prickly Pear plants. Within 0.1 mile of the main road east of 6-06, a low bedrock knob is covered with a dense stand of ironwoods.

S17. 7-06 In center of valley, many shallow rills drain SW. A sparse pebbly lag covers the surface. Elev 2300 ft. Sandy loam soil, uniform texture throughout, 75 cm td, with 6 cm dia rocks at bottom. Color 7.5 YR 7/4 dry. Very calc top to td. SA blocky structure in top 5 cm, apparently due to some cementation by clay.

Veg: creosote, abundant Christmas cactus, scattered saguaros, mammilaria, small catclaw acacia? acacia.

S18. 8-06 In divide between hills. A few rills, not deep. Elev 2245 ft. A sparse pebbly surface lag, and rocks in hole 1-4 cm dias. Td 82 cm, pebbly silt loams, loose. v calc throughout interval and color 7.5 YR 6/4 uniform. Slight structure - SA blocky in top 5 cm only, otherwise loose.

Veg: creosote with prickly pear, Christmas cactus, sparse bursage, cane cholla, a few teddy bear cholla. Scattered ocotillo, saguaros surround the creosote flat. Palo verdes only towards hillslopes and do not extend onto the flats. Some acacia along washes, and another shrub.

S19. 9-06 near to Avra Valley-Silverbell Rd. Elev. 2220 ft. A surface with abundant 2-3 m deep rills flowing eastward. Pebbly lag on remnant interfluves. Mostly limestone bedrock upslope, and soil is very calc. Td 40 cm, and a distinct color change in the hole:

0-28 cm is more tan, color about 7.5 YR 7/4, sandy silty loam with pebbles. No obvious buildup of red clay into a B horizon.

28-40 cm is more pink, 7.5 YR 7/2, with thin caliche coats distributed around pebbles, otherwise texture similar to above.

Nearby along road, a mature caliche hardpan layer exposed along road at a depth of about 30 cm below natural surface.

Veg: bursage and creosote, teddy bear cholla, saguaro, common ocotillo, cane cholla. Palo verdes along washes and scattered in interfluves. One unknown shrub.

S20. 1-18 - 1-1.5 m deep rills cross creosote flats. spotty pebbly lag, most areas without the lag.

0-90 cm - a loose silt loam with thin lenses of more red-brown silt-sand loam. Very calcareous entire 90 cm section, color near 7.5 YR 5/6 dry. Slightly blocky structure top 10 cm. Some lenses of more calc loams. Buildup of pebbles 1-3 cm dias within the top 10 cm. These have continuous caliche rinds. Appears to have eolian content, redeposited by sheet flooding.

Veg: creosote, mostly mounded, some bursage, whitethorn acacia along washes, Christmas cactus under creosote nurses, strong clumps of teddy bear, uncommon prickly pear, saguaros not on this surface but on other surfaces.

S21. 2-18 - higher on flanks of Pan Quemado Mts, In a shallow buried pediment reentrant. Sample site south of a concrete water catchment developed by Arizona Game and Fish Dept. Much teddy bear cholla along the entrance road, very thick patches in places in the flats. 100% pebbly lag cover around sample site, rocks as large as 1 meter diameter. Larger ones with some black varnish residuum, flaking away, some with residual calcrete coatings on bottoms showing through eroding soils.

0-66 cm - very similar to 1-18 soil, very silty loam, very rocky (2-5 cm dias), 20% of soil volume. Color 7.5 YR 6/2 or 7/2. Soil slightly damp top 10-15 cm.

Veg: mounded creosotes, scattered palo verdes, saguaros, clumps of teddy bear, scattered ratany, no bursage, one cane cholla (green).

S22. 3-18 - coluvial soil on north-facing hillslope, exposed on edge of recently eroded-out amphitheater. Pebbley rocky lag on surface, some rocks with 3 kinds of lichens on some rocks.

0-20 cm - very rocky silt loam, pinkish color, sl calc.

20-60 cm - strong petrocalcic cliff-forming unit with 50% coluvial lag, 50% calcrete, containing chunks of orange-tan sandstone bedrock from below. Rocks in petrocalcic horizon have strong calcrete undercoats on bottoms, to 1.5 cm thick.

Veg: ratany and bursage, common palo verde, ocotillo, cane cholla. Many palo verdes low on hillslope. Rare prickly pear, Christmas cactus, a few barrel cactus and mammilaria.

S23. 4-18 Three soil descriptions along a transect up a hillside, with very different vegetation cover, and distinctly different soils.

4-18 A - along flats near base of hill, with creosote cover on flats, and saguaro, bursage, cane cholla along drainages only. Top 53 cm of soil is weakly calcareous sandy loam with gravel lenses, loose, unconsolidated.

4-18 B - just upslope of lower edge of bursage and a 15 cm-tall native grass, near bottom edge of palo verdes, and near bottom edge of a strong pebble lag. 0-25 cm consists of very rocky clay loam to loam, colors darker with increased clays - 7.5 YR 4/6, non to weakly calc. Some rocks have light calcrete on undersides.

4-18 C - very rocky loams, 0-10 cm mod calc, no soil structures, sandy rocky loam. 10-40 cm, more rocky, very calc, with pebbles totally coated below 25 cm. 15 m west of here a hard calcrete surface exposed in wash, partly gully bed cementation, down about 50 cm below surface. In this hillside area, palo verdes common, concentrated along rills, with pockets of ocotillo, saguaros, barrel, cane cholla, small fishhook. Ocotillos and creosotes occur in separate pockets.

This hillside situation at 4-18 is a good example of the intricate and incompletely understood relationship between plant distribution and soil morphology.

S24. 5-18 low relief creosote flats, monotypic stand, some mounding of the plants. Slight possible gravel bar and swale morphology here, heavily degraded. Variable lag cover here, some rocks red on bottoms, some carbonate clasts in the lag. In the area of sample sites 5-18 and 6-18 is noted distinct and exclusive populations of either ratany or bursage, pointed out to me by Mark Dimmitt. The ratney is found on residual Pleistocene surfaces showing evidence of sheetflows and lacking extensive rills or arroyos. The bursage is developed in lower topographic settings where considerable widths of braided streams are found, subject to what should be greater and longer-lasting soil moisture conditions.

0-10 cm - non calc silt loam (eolian derived?), slightly pebbley, some blocky structure.

20-35 cm - mod calc, rocky silt loam, pebbles with some caliche coatings on bottoms. Hole stopped by big rocks.

S25. 6-18 - 0-30 cm - very calc very rocky loam, color 7.5 YR 5/6, pebbley lag on surface of flats, including carbonate pebbles.

Veg: ratany common, with creosote, slight mounding. Mudcracked siltstone surfaces in swales, sheet flooding and standing water present occasionally.

S26. 1-31 Atop a high residual interfluve, flat-topped, about 60 ft above nearby wash bottom. (E 1/2 S9,12S, 8E). Elev 2600 ft. Older, relict soils probably eroded from this narrow ridgeline, evidenced by chunks of Stage V caliche found on hillsides of other similar ridges nearby.

About 30 cm of loose silt loam, v calc, 7.5 YR 6/4 dry and 4/4 to 4/6 wet, over a buried hard calcrete layer about 2-3 meters thick. Bedrock lies just below on a pediment surface, consisting of Jurassic redbeds. Evidence of debris flow deposition in this area, with totally unsorted beds present.

S27. 2-31 SW of Malpais Hill, elev 2100 ft. 50 m east of major wash, incised 2 m below surface. Surface contains very slight swales and rills. Nearby to the NW bar and swale surface still evident, with 30 cm of relief between gravel patches and loose silts in swales.

0-10 cm - loose silty sandy loam, lots of fine roots, Color 5 YR 4/4 dry and 6/3 to 6/4 wet.

10-26 cm - pebbly loam, clay buildup, 5 YR 4/4 dry, 6/3 to 6/4 wet. Non-calc

26-36 cm - more granular - sandy loam, 7.5 YR 5/4 dry, 4/6 wet. Slightly calc, stage 1, with slight caliche rinds on base of pebbles.

Veg: ironwood, scat palo verde, common creosote, bursage, saguaro; rare ocotillo, barrel cactus, mamalaria.

S28. 3-31 On NW-sloping bajada near hills, elev 1960 ft. Wash more than 30 m away, incised 2 m. Slight desert pavement development, and remnant bar and swale obvious..

0-20 cm - very fine sandy loam, red clay lenses parallel to surface, mixed with more tan soil. Non-calc, and some roots. Color 5 YR 5/4 dry, 4/4 to 3/4 wet.

20-28 cm - very fine sandy loam, same color as 0-20, slight calc.

28-38 cm - similar to 20-28, stage 1 caliche development, spotty caliche lenses.

Veg: creosote, fewer bursage than 2-31, ironwoods along washes, teddy bear cholla, barrel cactus.

S29. 4-31 On low relief, very shallow incised bajada on north flank of West Silverbell Mts, but no local rills, probably sheetflood deposition. elev 1870 ft. Old degraded bar and swale present, no rills in area. The surface here is aggrading.

0-50 cm - uniform very fine sandy loam, rocky throughout, caliche rinds on bottoms only in lower part below 42 cm. Acid reaction - none 0-10, slight 10-20; vigorous 20-30, very vigorous 30-50 cm. Color 5 YR 6/4 to 7.5 YR 6/4 dry; 5 YR 4/4 to 7.5 YR 4/4 wet. No obvious B horizon with clay buildup.

Veg: creosote, rare saguaro, rare teddy bear cholla, streams lined with palo verde, ironwood. (no bursage?)

S30. 5-31 30 m S of Monument boundary, elev 1775 ft. Nearest wash incised 1 m, located 20 m to west.

0-57 cm - sandy loam soil, similar to 4-31 with increasing caliche with depth, Stage 1 caliche below 30 cm, stage 1-2 at bottom, same colors as 4-31.

Veg: monotypic creosote, slight mounding; ironwoods and palo verde along washes.

S31. 6-31 On pediment on NE flank of West Silverbell Mts, elev 1870 ft, and slope is 20 ft of fall in 700 ft horizontal or about 3%. Surface lag is coarse grus, 1-2 cm dias.

Top 15 cm is loose. Coarse sandy loam, grus (granite derived), 5 YR 4/4 dry, 6/4 wet.

15-30 cm - slight calc, concentrated roots medium size, coarse sandy loam.

30-54 cm - no caliche visible but vigorous reaction, a coarse sandy loam. Pebbles have no caliche on undersides.

Veg: palo verde, saguaro, no ironwoods. Creosote, bursage, cane cholla, ocotillo, one barrel cactus.

S32. 7-31 In pediment or bajada gap in West Silverbell Mts, near saddle, elev 1930 ft.

0-50 cm - Rocky pebbly sandy loam, caliche build up downward from 5 to 50 cm slight to vigorous. Same color throughout 5 YR 6/4 dry, 4/4 wet. Big roots to 5-8 mm dias at 30-40 cm, but most smaller roots at 15-25 cm.

(no veg noted)

S33. 8-31 Area of old degraded bar and swale.

0-15 cm - fine sandy loam, 7.5 YR 6/4 dry, 4/4 wet.

15-50 cm - fine sandy loam, 7.5 YR 4/4 dry, 3/4 wet. Moderate calc 15 to 50 cm, with slight reaction in top 15 cm.

Veg: creosote, bursage, patchy saguaro, ironwood and palo verde along washes, single teddy bear cholla, and one came cholla.

S34. 1-31 M (M = March '03)

westward on Mile Wide Rd. 0.6 miles west of gates into Ironwood NM, road crosses a small playa, subject to flooding after rains.

0-75 cm - fine sandy and silt loams, 10 YR 5/3 dry, non-calc. A damp zone at about 10-20 cm depths.

75-125 cm - clay loam to clay, very calc, dry, loose and powdery, no structure. 10 YR 6/3 to 7/3 dry.

Veg: surrounding the playa, creosote, staghorn cholla, occasional stunted mesquite. A few mounds in the playa, where apparently grew mesquites in the past.

S35. 2-31 M - creosote flats, sheetflooded occasionally, rills sparse and shallow. No real pebble lags on surface. Low relief mounds of cemented soils (not obvious former sites of creosote plants), surrounded by extensive swales covered with med-coarse clean washed sand to 1 cm thick. Origin of this washed sand layer unclear, not obviously from eolian source. In this general area (noted for some distance along the road to the northwest of this sample point) is residual bar-and-swale structure, consisting of long ribbons of gravel bars and gentle lower elevation sandy swales, particularly well noted in the southeast quarter of section 18. This is a typical condition on the surface of an actively depositing alluvial fan.

•  cm - loose clean washed coarse sand.

1-60 cm - sandy loam, loose, non-structured, damp at 15-30 cm, 10 YR 5/4 dry, non-calc, few sub-angular peds to 2 cm dias from near bottom, very weakly calc.

60-115 cm - same texture as above, very dry, colors slightly lighter, 10 YR 6/3 to 7/3, but mod to very calc. A very loose, dry, unstructured silt loam to clay loam.

Veg: creosote flats, slightly to non-mounded, some mesquites to 10 ft tall concentrated along rills, also rare white thorn acacia along rills.

S36. 3-31 M - upslope on same surface as last sample. West of a major wash, the road rises onto a very slightly steeper valleyward-sloping surface (very hard to measure, and not obvious on the 7.5 minute topo map), and at that topographic break, bursage very quickly appears on the higher elevation side and soon dominates as the shrub or subshrub.

A pebbley to coarse granule surface lag, partial cover only.

0-25 cm - slightly pebbley very sandy loam, hard to dig, collapses easily. Non-calc, 7.5 YR 5/4 to 10 YR 5/4. Very loose, unstructured.

25-70 cm - similar to above, increasing pebble fraction, slightly lighter in color, 7.5 YR 5/4. Slight to mod calc.

0-70 cm is a very sandy loam, possibly reworked from nearby sand dunes, though no evidence otherwise seen of their presence.

Veg: diversity greater here. Abundant bursage, with sparse creosote, teddy bear,12 ft mesquites, common, 2 barrel cactus, few staghorn chollas. No saguaros or ironwood nearby.

S37. 4-31 M - Nearing Cocoraque Butte. In an healthy ironwood thicket, many young trees. South side of road by 30 yards. Subject to sheetflooding, with gentle swales, few nearby rills. Some sparse pebble lag, mostly granule and coarse sand lag.

0-40 cm - very pebbly (to 3 cm dias) very sandy loam, loose and structureless, color 10 YR 5/4 to 5/6. Coarse sand to granules fraction increases in bottom 10 cm. Very slightly calc at surface, increases downward to moderate at total depth. Hole caves in with loose sand at td.

Veg: ironwood, many small to mature trees, creosote, bursage, staghorn cholla, uncommon saguaro, occ mesquite. (Saguaros common downslope and upslope.)

S38. 5-31 M - Farther northwest, and northwest of Cocoraque Ranch Hqs., and just west of El Cerrito de Gallinas hill. A creosote flat, nearer the Roskruge Mts. Sparse pebble lag on surface. Sheet-flooded, no rills visible. Very similar soil to 4-31 M, depth to 60 cm (hit rock), slightly more pebbly, and with perhaps slightly more caliche content at all depths.

Veg: creosote and scrub mesquite, rare saguaro.

S38A. 6-31M - [note only] - along the main road, on the bajada on east side of Dos Titos peaks of nearby section 29, and near Agua Blanca and Agua Dulse Ranch headquarters (secs17, 21, 22, 27, 35, T13S, R9E, Waterman Peak 7.5 map) frequent outcrops along major washes of deep buried caliche (1-2 m down below current surface, and irregular outcrops of volcanic bedrock. This mountain front is lined with some late Pleistocene alluviums (bajadas) overlying shallow buried pediment surfaces. In sections 21 and 22 along this transect, patchy outcrops of dark red brown paleargid 'Bt' soils, exposed in swales between extensive cove of desert pavements, clearly a remnant mature Pleistocene soil, now exposed at the surface and eroding. The interplay between creosote patches and mesquite-ironwood-saguaro concentrations along this transect is striking.

S39. 1-10 Apr - Creosote-bursage flats, sloping gently away from the Silver Bell Mts, with the limestone hill of the West Silver Bell Mts (NW 1/4 sec 34) about 1 mile east of the site. Scattered pebble lag on the surface, and well-developed bar and swale structure (indicative of active alluvial fan deposition), with long axes of gravel bars trending 340 deg and 280 deg azimuths, by direct measure. In gravel lags, an occasional black/red varnished pebble noted, often overturned.

0-75 cm - uniform dry to damp silt loam, pebbly (1-3 cm dias). Loose, nearly dry, structureless all the way, with damp zones noted at 15-25, 50-75 cm depths. Colors near 7.5 YR 5/6. The material is without obvious soil buildup, except minor crusts on modern surface, and may represent modified eolian dune sands-silts. Buried pebbles may be concentrated in discreet layers which might be thin mudflow deposits.

Veg: creosote, bursage flats, few barrel cactus, jumping chollas. Nearby riparian zone to the north with palo verdes, saguaros, ironwoods. Few small palo verdes and ironwoods along very shallow rills traversing the flats.

S40. 2-10 Apr - creosote flats, some with low mounding, 200 ft SSW of section corner, some light pebble lag. Rills cut 1 to 1.5 m deep into flats.

0-76 cm - uniform very sandy silty loam, slightly pebbly (1-2 cm dias), no structure except blockiness top 3 cm. Color 7.5 YR 5/6, non calc to total depth. (As in last sample, this may represent reworked eolian silts-sands. Surface not old enough for soil formation.

Veg: creosote flats, none to slight mounding, with two kinds of bursage, white bursage dominant. Along washes 100 m north are ironwoods, mesquites, no saguaros.

S40A. 2A-10 Apr - Note on groundwater from well located at or near the exact center of south edge, section 22, T11S, R6E, elevation about 1733 ft (Gap Tank Quad): Cotton-wheat farm managed/owned by Ray Farnsworth whose house is at the road intersection one mile north. He reports the water table now at about 250 feet, the water for irrigation always at a temperature of 99 degrees F. TDS values unknown, but low. Touching the water at the well head confirms the water is warm. There must be deep circulation of a fraction of this water. Ray says there is a bedrock high to the north in the valley, which ponds the water to a higher water table elevation in his part of the valley. This feature could confine deep water rising from lower in the basin to this area.

S41. 3-10 Apr - on Aguirre flats south of the active farms. Creosote flats traversed by shallow arroyos 1-2 m deep. Creosotes with some mounding. There is a gray sand lag deposit covering a light red-brown crusty soil surface. A 3-4 m deep arroyo 30 m to west, flows north. 3 m of stratigraphy exposed in the arroyo, very similar to soils noted below, but a light gray-tan stage 2 calcrete about 2 m down in the profile, at least 20 cm thick, base buried.

0-60 cm - slightly pebbly sandy loams, loose, won't pack into auger. Colors alternate - 7.5 YR 5/4 to 6/4 (shallower). Very slightly calcareous near top.

50-60 cm - slightly more calcareous, mod calc at bottom, sandy loams, 7.5 YR 5/4. Blocky structure in layers at 5-15 cm, 50-60 cm, and a very loose sandy layer at 20-35 cm.

Veg: nearly monotypic creosote flats, few hackberry, rare barrel cactus, no saguaro, no ironwood. Mesquite thickets along nearby arroyo, narrow bands of bosque, with atriplex polycarpa, and abundant healthy graythorn with leaves and red berries. Small playas in area, with dead vegetation.

S42. 4-10 Apr - near middle of one-acre playa surface, 20 m west of road that crosses the surface. Dead mesquites on the surface of the playa, interpreted to indicate that standing water at some time killed the plants. A very sparse pebble lag on the surface might indicate moving water of some depth from time to time. The playa surface is covered with a fine layer of dried mud, (7.5 YR 6/4 to 6/6), and contains mud cracks 3-12 cm diameters.

(This soil, note decrease of caliche content with increasing depth)

0-35 cm - silt loam to loam, moderately calc, 7.5 YR 6/6, with some blocky structure in upper part, peds to 1 cm dia.

35-55 cm - fine sandy loam, non-calc, 7.5 YR 5/6, some blocky structure, peds to 2 cm dia.

55-65 cm - loose med to coarse sand with minor loam component, non-calc, color near 7.5 YR 5/6. Not pure eolian, some kind of reworked sheetflood sand deposit.

Veg around playa: small mesquites, creosotes.

S43. 5-10 Apr - Visita site (according to J. Jefferson Reid, U of A professor of archaeology): five-acre mini-playa surface at far south end of Ironwood NM near its boundary with the Indian Reservation. Soils were not sampled here. Vegetation includes a lone crucifixion thorn growing on the west side of the playa. The western part of the playa is covered with a scattered gravel lag deposit, and a few of the rocks contain a relict desert varnish (black and shiny), but no obvious reddening on their bottoms. The lag contains a few well rounded pebbles of quartz and quartzite 1-2 cm diameters, from an unknown source.

The rocks used as the foundation course of the visita structure are not from nearby, as the ground surface and arroyo bottoms are sandy. The rocks are all very angular and broken, and probably derive from bedrock exposures of the Santa Rosa Mountains to the west, 3-4 miles distant. Because the visita site is currently totally surrounded by a playa surface, the question may be asked concerning the degree of flooding and sedimentation after site abandonment, and the amount of buried archaeology at the visita. It seems possible that the site was not a playa when it was active.

S44. 6-10 Apr and 7-10 Apr - (A) the thicket about 100 m west of the road, composed of 2 m tall dwarf mesquites, normal to large creosotes, wolfberry and white thorn acacia, is a curious community. Where penetrated on foot, it is clearly subject to sheet flooding, and is the only area in this study seen to be subject to soil piping, whereupon shallow buried channels carry soil particles away, towards heads of arroyo, with subsequent collapse of some segments, producing elongate collapse 'troughs'. This effect seems more prevalent in the thickets than elsewhere. Nearby (to the east) unvegetated flats contain no evidence of the rills, arroyos, or piping channels. To understand the flow of sheet flooding in this area a map of rills and fine-scale level surveying would have to be done.

•  At this site is noted some archaeological remains . Near the west side of the road is a broad scatter of pot sherds, some found in several potential trash or refuse piles; at least four pottery types present, including orange-brown and red-brown colors (unpainted), and a gray colored type, with 30-40% grog that consists of shiny slate or phyllite, producing a handsome sheen effect produced by a final rubbing that alined the particles with the surface during manufacture. Also present are sparse stone flakes (aphanitic dark volcanic rock), and a few broken fragments of white sea shell pendants with drill holes. ( a lat-long determined for this spot by Mark Dimmitt is: 32 deg 24 min 19.1 sec N; 111 deg 45 min 42.4 sec W).

•  Nearby, farther west, and near the east edge of the above mentioned mesquite thicket, are several curious groupings of what appears to be sticks purposefully buried or inserted into the ground, 1-2 feet tall, some on gentle earthen mounds, some on flat ground. On one curious elongate mound, some buried sticks seem to be mixed in with natural stalks of some dead plant (creosote or mesquite) that grew there at one time. No sherd concentrations were noted here, nor anything else which might suggest human shelters or structures may have been present. This site is about 2.0 miles due north of the stone foundation identified as a visita for San Xavier Mission priests.

Another curious phenomenon was noted at this site. Less than 100 ft west of the road is a most curious drainage alignment (trending about N 10-20 degrees W, almost parallel to the modern road), consisting of a very straight segment of arroyo with strange 'V' shaped cross-section, and now eroded about 2.5 m deep. The drainage does not have a natural arroyo cross section shape, and runs in a very straight line for several hundred meters. Up-valley it turns to a more southeasterly direction, and is joined by several side branch arroyos. It traverses through the pot sherd concentration. Might it represent an old wagon road? Within this drainage were noted 2-3 broken parts of a definite stone mano, scattered for some meters along its length.

S45. 8-10 Apr - just below interface of toe part of bajada slope coming from Santa Rosa Mts, and creosote flats and braidplain or 'floodplain' of Aguirre Wash. Soil examined within 15 m laterally (east of) of this interface. This spot near (within 100 m) the local NW corner of Ironwood NM. No pebbly lag deposits at all, material appears to be granite-derived grus.

0-18 cm - silt loam, blocky-tabular structure, top 5 cm sl. calc, 10 YR 5/6 to 6/6

18-24 cm - loose fine to med sand, same color as above, non-calc.

24-65 cm - sandy clay loam, color intensifies to 7.5 YR 5/6 with clay buildup, few 2 cm pebbles, totally non-calc. There should be a buried caliche within 2 m.

Veg: below ecotone, creosote bursage flats with some 30 cm-deep rills downslope, a few mature ironwood trees, and a rare occurrence in the Monument of a barrel cactus (Mark Dimmitt), and rare saguaro. Above the ecotone, and along arroyos, mesquites, saguaros, whitethorn acacia, wolf berry, globe mallow flowering, brittlebush, canyon ragweed.

S46. 9-10 Apr - area typical of the parts of the valley where small spots lacking all vegetation are commonly encountered. See text section for description.

S47 11 May -01 examine area which appears anomalously white in color on the aerial photos, near high voltage power line, in Aguirre Valley. This area of light surface color mapped on the enclosed geologic map. The very light color due to a pebble lag soil surface coating that is made of decomposed granite and volcanic rocks that are all very light in color. The sediment underneath is a uniform red-brown color, and the white color appears only where the lag gravel covering is sufficiently thick.

At sample site, the biggest arroyo is 100 m to north, 1.5 to 2.0 m deep below this surface. Surface covered with discontinuous patches of pebble lag, which may or may not represent old bar and swale. In part the pebble lag is very light in color. At the borehole below, the light color of the surface lag is only one pebble deep. Buried pebbles coated with clay.

Soil is rather uniform rocky pebbly silt loam, uniform texture, loose, no structure except crusty top 1 cm, non-calc at surface, mod calc at 1.0 m depth. Color uniform 7.5 YR 5/6. The sediment is slightly damp and darker at 25-45 cm depth, and last rain was several weeks ago.

Veg: monotypic creosote, mounded, scattered far apart. Along washes is palo verde, ironwood, some concentrations of saguaro.

S48 11 May -02. Area of developed desert varnish on patches of desert pavement. This is the darkest varnish noted in the Monument. A number of E-W elongate patches are found on the south side of the road and visible from it (20-100 ft south), and a few less developed patches on north side. The patches are composed of a moderately packed gravel and rock surface. Many 1-2 cm dia pebbles are very black and shiny, larger rocks (to 20 cm dia) are quite black on top surface, intense red-brown on bottom. There is a lot of turn-over, as many red surfaces are up. An animal track leads through the pavement parallel to the road, but no fresh tracks obvious. Bursage grows through the black patches, but creosote is found at edge of patches in many spots, with no pavement or varnish for one meter from creosote - some rodent burrowing disrupts the pavement. Saguaro stands seem to avoid the overall pavement concentration, grow only at the edge. Sediments exposed in arroyos nearby (0.5 m deep) are 7.5 YR 5/6 sandy loams, non to slight calc in top 30 cm. In adjacent

Veg: creosote (slight mounding), bursage, palo verde, saguaro, teddy bear cholla, cane cholla.

In adjacent SE quarter section 21, just downslope and near the road, the desert pavement has been buried beneath a foot of muddy sediment, which is itself now being washed away into shallow (1 m deep) nearby rills. The pavement which is being re-exposed by the erosion contains some dark varnished rocks. Creosotes sitting on the mud surface display mounding.

S49 23 May-01 sand dunes with dune structure still preserved, at least 4 m thick (perhaps 6 m?), piled against hills at base of Wildcat Peak. Northernmost dune is covering (to its north) a south-dipping Pleistocene varnished pavement surface, and dunes thin to the south and merge with, about a mile south and west, a playa surface (elev 1600 ft). The dune field covers about 1/4 of a section, mostly in SW 1/4 sec 9, a bit of E 1/2 sec 8, and some of NW 1/4 sec 16. About 3 meters of relief on the dunes, which are transverse, with presumed winds from the southwest off the playa.

0-50 cm - loose unconsolidated medium sand, well sorted, but apparently arkosic, with some very weak angular blocky structure, but all totally non calcareous. Color weaker at surface, intensifies downward to about 5 YR 5/6. Very slightly damp below 30 cm. Hole caves easily, hard to dig.

Dune veg: palo verdes in shallower sand areas, in thicker sand is a 3 ft tall grass, prickly pear, healthy bursage, barrel cactus, a cane cholla. Two unknown shrubs. Big galleta grass where dunes are thick. No saguaros. Dunes heavily vegetated now, probably moved during drier parts of Holocene, as a very sharp boundary at north edge of field, where dunes are covering the pavement surface.

S50 23 May-02 surface with thin scattered slightly varnished pebble and rock lag, mixed with sags filled with thin sandy-silty deposits. Lots of small rocks on surface consist of angular caliche chunks, very angular, 1-2 cm dias.

0-30 cm - hole stopped by big rocks. Material is angular chunks of caliche, dispersed along with rocks (1-15 cm dia) in a silt loam matrix, totally loose, all very calcareous, color 7.5 YR 6/4.

Veg: mounded creosotes, ratany, barrel cactus, scattered palo verdes, rare saguaros, both concentrated along washes.