These excluded, still leave a very wide range of silt, clay, and loam soils, most of which are suitable to cacao culture.
"Cacao Culture in the Philippines"
William S. Lyon
Clearly these tadpoles are unsuited for life in ponds or sluggish streams in the lowlands, where the temperature of the water is high, a layer of silt on the bottom is deep, and the amount of oxygen is low.
"A Review of the Middle American Tree Frogs of the Genus Ptychohyla"
William E. Duellman
There is no reason to doubt, therefore, that shale is merely compacted silt and mud-the sediment deposited by water.
"Geology"
James Geikie