=116. Kinds of soils.= It is very doubtful whether it is worth while to attempt to distinguish soils upon the basis of mechanical analysis. Unquestionably, the most satisfactory method is to distinguish them with respect to holard and chresard, and to regard texture as of secondary importance. A series of soil classes which comprise various soil types has been proposed by the U. S. Bureau[7] of Soils as follows: (1) stony loam, (2) gravel, (3) gravelly loam, (4) dunesand, (5) sand, (6) fine sand, (7) sandy loam, (8) fine sandy loam, (9) loam, (10) shale loam, (11) silt loam, (12) clay loam, (13) clay, (14) adobe. These are based entirely upon mechanical analyses, and in some cases are too closely related to be useful. The line between them can nowhere be sharply drawn. Indeed, the variation within one class is so great that soils have frequently been referred to the wrong group. Thus, Cassadaga sand (gravel 22 per cent, sand 43 per cent, silt 21 per cent, clay 10 per cent) is more closely related to Oxnard sandy loam (26–37–18–12) and to Afton fine sandy loam (28–43–18–8) than to Coral sand (61–29–3–4), Galveston sand (6–91–1–1), or Salt Lake sand (84–15–1–0). Elsinore sandy loam (8–38–35–10) is much nearer to Hanford fine sandy loam (9–36–33–14) than to Billings sandy loam (1–60–22–11) or to Utuado sandy loam (48–23–19–8). The soil types are much more confused, and for ecological purposes at least are entirely valueless. Lake Charles fine sandy loam has the composition, 1–34–52–9; Vernon fine sandy loam, 1–37–54–7, while many other so-called types show nearly the same degree of identity.