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Updated: June 3, 2025
The great dirt-bed or vegetable soil containing the roots and stools of Cycadeae, which I shall presently describe, underlies these marls, and rests upon the lowest fresh-water limestone, a rock about eight feet thick, containing Cyclas, Valvata, and Limnaea, of the same species as those of the uppermost part of the Lower Purbeck, or above the dirt-bed.
The upper division of this group consists in great part of beds of compact, fragile limestone, with some intercalated green marls. The shells in some parts are a mixture of Cerithium, Cyclostoma, and Corbula; in others Limnea, Cerithium, Paludina, etc. In the latter, the bones of reptiles and mammalia, Palaeotherium and Lophiodon, have been found.
The gypsum quarried there for the manufacture of plaster of Paris occurs as a granular crystalline rock, and, together with the associated marls, contains land and fluviatile shells, together with the bones and skeletons of birds and quadrupeds. The remains also of fresh-water fish, and of crocodiles and other reptiles, occur in the gypsum.
It consisted of sandstone marls, red, blue, green, orange, purple, white, brown, lilac, and yellow, interstratified with magnesian limestone in bands of purple, bluish-white, and mottled, with here and there shining flecks or great glares of gypsum. Among the more delicate wonders of the scene were the petrified trunks which had once been pines and cedars, but which were now flint or jasper.
But the rashness of pretending to identify, in age, all the red sandstones and marls in question, has at length been sufficiently exposed, by the discovery that, even in Europe, they belong decidedly to many different epochs." Nevertheless, while in this and many kindred passages Sir C. Lyell protests against the bias here illustrated, he seems himself not completely free from it.
It was before stated that the Miocene formation of Switzerland consisted of, first, the upper fresh-water molasse, comprising the lacustrine marls of Oeningen; secondly, the marine molasse, corresponding in age to the faluns of Touraine; and thirdly, the lower fresh-water molasse. Some of the beds of the marine or middle series reach a height of 2470 feet above the sea.
Plains and hills and cliffs and distant mountains seem to be floating vaguely about in a trembling, wave-rocked sea, and patches of landscape seem to float away and be lost, and then to reappear. Just opposite, there are buttes, outliers of cliffs to the left. Below, they are composed of shales and marls of light blue and slate colors; above, the rocks are buff and gray, and then brown.
It was a land of desolation an extension of the Mojave Desert on the south, and the alkaline flats and mineral mountains of Nevada on the north, of Death Valley and the Funeral Mountains of California to the northwest a burned-out land of grim-looking mountains extending north and south across our way; a dried-out, washed-out, and wind-swept land of extensive flats and arroyos; a land of rock and gravel cemented in marls and clay; ungraced with any but the desert plants, cactus and thorny shrubs, with little that was pleasing or attractive.
For us, we could only give a hasty look at its southern volcanic cliffs; while we regretted that we could not inspect the marine strata of the eastern parts of the island, with their calcareous marls and limestones, hardened clays and cherts, and famous silicified trees, which offer important problems to the geologist, as yet not worked out.
Bent and undulating gypseous marl. g. Gypsum. m. Between San Caterina and Castrogiovanni, in Sicily, bent and undulating gypseous marls occur, with here and there thin beds of solid gypsum interstratified.
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