The soil, a Typic Calciorthid, is sandy loam overlain by a thin pavement of fine 

 and medium gravels. A weak felt of filamentous algae, scarcely detectable to the un- 

 aided eye, occupies the soil surface between the gravels to a depth of about 2 mm. (This 

 element's contribution to total organic mass is minor and is not included in this 

 study.) The top soil horizon, to 7 cm., has a fine-platy, somewhat vesicular structure. 

 Below this, to 30 or 40 cm. (wavy, abrupt lower boundary), the soil is without structure, 

 loose, and single-grained. Both of these horizons contain a few fine and medium gravels. 

 They have a bulk density of 1.35 g./cm.^. Their light color is evidence of little humus 

 accumulation. Immediately below is a strongly developed white calcic horizon, hard where 

 particles are fine, more fragile where they are clean, coarse sand. This horizon extends 

 to an irregular lower boundary 75 to 115 cm. below the surface. Its texture varies 

 considerably over short distances. The original stratification of the alluvium is 

 obvious. Most strata are comprised of sands and finer particles; some have high percen- 

 tages of medium or coarse gravels embedded in the finer material. Noncemented lenses of 

 sorted coarse sand or fine gravel occur irregularly. Textural and structural heteroge- 

 neity have resulted in irregular distribution of roots in this horizon. Roots can be 

 absent from hard and massive portions, but abundant in the loose sand lenses or 

 immediately beneath some of the larger gravel particles or cobbles. Below the calcic 

 horizon, the alluvium is stratified sand and gravelly or cobbly sand along with occa- 

 sional thin (2 to 6 cm.) laminations of lime-cemented fine material; the lowest of the 

 laminations was seen at a depth of 150 cm. in a pit 185 cm. deep. 



The open cover of discrete plant units is dominated by Atriplex oonfertifolia 

 (Torr. and Frem.) S. Wats., a rounded shrub 20 to 30 cm. high. The subshrub Euvotia 

 lanata (Pursh) Moq. and the bunchgrass Oryzopsis hymenoides (Roem. and Schult.) Ricker 

 are subdominant. Other perennial shrubs and herbs are infrequent. Annuals, among them 

 Salsola kali L., Halogeton gZomeratus (Bieb.) C. A. Meyer, and Machaeranthera oanesaens 

 (Pursh) A. Gray, are never abundant in this ungrazed perennial cover and do not appear 

 in some years. The woody species are winter-deciduous. About 15 percent of the ground 

 is shaded by standing plant material, of which half is dead crovrm cover. 



Underground material was sampled from plots selected for homogeneity of cover. 

 Small patches of uncomm.on or irregularly occurring species were purposely avoided, as 

 were sites of current or recent burrowing by kangaroo rats and pocket gophers. 



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