Page:A Treatise on Geology, volume 2.djvu/58

 44 worked. "In this upper gypsum fossil insects occur exclusively in a finely laminated bed of 2 inches in thickness: still lower are two other ranges of gypsum, the upper one of which alone is worked; the marls associated therewith contain nearly as great a quantity of fishes as those of the upper calcareous zone. Beneath these are beds of white and pink coloured marlstone and marl, inclined at 25° to 30°, containing Potamidum Lamarckii, and Cyclas aquæ Sextiæ; and these pass downwards into a red sandstone and coarse conglomerate. The fundamental rock of the whole district is a secondary limestone, with belemnites, gryphites, and terebratulae." In the contemporaneous lignites of Faveau, Planorbis cornu, P. rotundatus, Melania scalaris, cyclades, and a unio occur; thus rendering the resemblance of the testacea of this deposit to those of the Upper Parisian freshwater beds very striking.

The insects of this deposit consist of Coleoptera 20 species, Orthoptera 8, Hemiptera 20, Neuroptera and larvæ, Hymenoptera 8, Lepidoptera 2, Diptera 15; there are also Arachnida. In the opinion of Marcel de Serres and Curtis, they are almost entirely included in genera now living in the south of Europe; and several species, as Brachycercus undatus, Acheta campestris, Forficula parallel, and Pentatoma grisea, are supposed to be identical with living types.

The freshwater beds of Alhama yielded to colonel Silvertop—

And at Teruel. Aragon, occur—

Limnæa pyramidalis.

In the freshwater beds of Cantal, according to Lyell and Murchison, are found—

Potamidum Lamarckii.