Elements of geology, or, The Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments elementsofgeolog00lyel Year: 1868 && a. Pupa vetusta. Dawson. Nat. size. &. The same, magnified. o. View of the depressed apex. d. Surface stria?, magnified 50 diam. e. Surface strise, of the recent English Pupa juniperi for comparison, magnified 50 diam. f. Microscopic structure of the shell, showing hexagonal cells, magnified 500 diam. of coal. This lower bed is an underclay V feet thick, with stigmarian rootlets, and the small land-shells occu
Elements of geology, or, The Elements of geology, or, The ancient changes of the earth and its inhabitants as illustrated by geological monuments elementsofgeolog00lyel Year: 1868 && a. Pupa vetusta. Dawson. Nat. size. &. The same, magnified. o. View of the depressed apex. d. Surface stria?, magnified 50 diam. e. Surface strise, of the recent English Pupa juniperi for comparison, magnified 50 diam. f. Microscopic structure of the shell, showing hexagonal cells, magnified 500 diam. of coal. This lower bed is an underclay V feet thick, with stigmarian rootlets, and the small land-shells occurring in it are in all stages of growth. They are chiefly confined to a layer about 2 inches thick, and are unmixed with any aquatic shells. They were all originally entire when imbedded, but are most of them now crushed, flattened, and distorted by pressure; they must have been accumulated, says Dr. Dawson, in mud deposited in a pond or creek.* The late Prof. Quekett, to whom I submitted the first specimen found in 1852 for microscopical examination, observed that the surface striae, on being magnified 50 diameters, d, fig. 561, presented exactly the same appear- ance as a portion corresponding in size to the common English Pupa juniperi (e, fig. 561), and a cross-section of the fossil shell (/, ibid.) Kg. 562.
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