> as lemmas

1873 Amer. Jrnl. Sci. 106 288 It makes a material difference whether the grains of sand contained in a soil or clay are prevalently half a millimeter in diameter, or the tenth or twentieth part of that amount. Sand (or more properly silt) of the latter size is by no means impalpable.

1909 A. G. McCall Physical Properties of Soils 88 Stir up the soil remaining in the centrifugal tube and allow to stand for about one minute, or until all particles larger than silt (0·05 [mm.]) have settled.

1920 A. Holmes Nomencl. Petrol. 211 Siltstone, a very fine-grained sandstone, the particles of which are predominantly of silt grade.

1958 I. W. Cornwall Soils for Archaeologist xi. 125 Once the silt-grade is reached (below 0·06 mm.) a moderate wind is able to transport the grains..for long distances.

1967 Gloss. Highway Engin. Terms (B.S.I.) 23 Silt. (1) A natural sediment of grading finer than sand consisting of granular products of rock weathering: it is gritty to the touch. (2) In soil analysis it comprises the fraction between 0·06 mm and 0·002 mm.

1968 R. W. Fairbridge Encycl. Geomorphol. 675/1 Primary forms of lime include minute grains, incrustations on silt-size grain aggregates and snail shells.

1971 Gloss. Soil Sci. Terms (Soil Sci. Soc. Amer.) 15/1 Silt, a soil separate consisting of particles between 0·05 and 0·002 mm in equivalent diameter.

1972 J. G. Cruickshank Soil Geogr. ii. 55 The products of physical weathering are usually large on the particle size scale; that is, they are stone, gravel, or sand size and less commonly as small as silt size.

1976 L. F. Curtis et al. Soils Brit. Isles i. 3 The mineral matter [of soil] includes particles of clay (less than 2 μm diameter), silt (2–50 μm diameter) and sand (50 μm–2 mm diameter).