Page:A Treatise on Geology, volume 2.djvu/67

 CHAP. VI. {| style="font-size:85%;line-height:140%;border-style:none;text-align:justify;" cellspacing="0" cellpadding="2" |- shells; (mammalian remains in great abundance. (Ilford, Copford, and Grays, in Essex, Stutton in Suffolk.)
 * || shells, with a small proportion of extinct
 * style="white-space:nowrap;" valign="top" | SECTION II. ||
 * || 5. Red crag. (It contains mastodon, &c.)
 * || 6. Coralline crag.
 * || 7. London clay. (It contains quadrumana, &c.)
 * || 8. Plastic clay.
 * }
 * || 6. Coralline crag.
 * || 7. London clay. (It contains quadrumana, &c.)
 * || 8. Plastic clay.
 * }
 * || 8. Plastic clay.
 * }
 * }

Some small lakes are situated at this day, and many were in former times, so as to receive no considerable river, but many small runlets from the adjacent slopes. Under ordinary circumstances, the running streams throw into lakes only carbonate of lime, and other dissolved or suspended matters, which may be diffused with great equality in the water, and at length settle on the bottom in one or more layers. In times of abundant rain, coarser sediments are carried into such lakes from more numerous points of the margin, and thus the whole lake is filled toward the edges by narrow concentric sloping layers of sand and gravel (s), which are intermixed with layers of finer clay or marly substance (c), as in the diagram No. 80.; which also shows, above several deposits of coarse and fine earthy