The coal measures Amphibia of North America / by Roy Lee Moodie.

  • Roy Lee Moodie
Date:
1916
Catalogue details

Licence: In copyright

Credit: The coal measures Amphibia of North America / by Roy Lee Moodie. Source: Wellcome Collection.

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    specimens of Pecopteris, are found quite definitely localized. These nodules are apt to assume an irregular shape. These localizations of the fossils are, of course, what we would expect from our knowledge of the recent fauna and flora. There is, to be sure, more or less intermingling of the species. The myriapods, so far as they have been found, are also localized. Mr. Carr found 3 within a space of a few feet, but again these are found widely scattered. The exposures at the “upper beds” are about a quarter of a mile long. They disappear under a heavy ledge of sandy limestone. At the “lower beds’’ (plate i, fig, 6), those further down the creek, conditions are quite different from those just described, although of the same horizon; the banks of the creek are higher and almost perpendicular, so that the chances of collection from the shales are fewer. The bed of the creek, however, is wider and there are more nodules washed out. The most abundant fossil at this place is Neuropteris. The nodules at the upper end of the exposure are all, almost without exception, barren of fossils. The exposures here are of about the same extent as the “upper beds,’’ though the species are not so varied. Judging from the collections made while there, Arthropoda are more abundant at the “lower beds.’’ Bradley (Geol. Surv. Illinois, iv, 196, 1870) mentions the occurrence of these nodules at or near Morris. Other than these places the nodules have been thrown out of a coal mine near Braidwood, Illinois. Doubtless close search would reveal other localities where the shale is cut through in mining. The beds at both places are slightly folded. This is true especially of the “upper beds,’’ where a conspicuous fold caused the beds to disappear in the bed of the creek and to reappear farther down stream. This is directly across the large “ox-bow” bend of the creek. The beds at Mazon Creek were first explored in 1857 by Mr. Joseph Evans, who sent his specimens to Berlin, Germany, where they excited great interest. It was he who collected the type specimen of Amphihamiis grandiceps Cope. Since the time of Mr. Evans many have collected at Mazon Creek, and without doubt the fossil-bearing nodules from this locality are more widely scattered in the museums of the world than are organic remains from any other one horizon. So far as we know there was no upland vertebrate life at that time. The forms at present known were confined to the water or the margins of the water. The absence of knowledge of upland and terrestrial deposits of this time doubtless accounts for the absence of known vertebrates. It is, however, especially interesting to speculate on the ancestral types of the land vertebrates, and it must be admitted that the Coal Measures Amphibia as at present known throw the ancestry of land- living vertebrates far back into geological time. ini) The Cannelton slates of Beaver County, Pennsylvania, have furnished 3 species of Amphibia and fragments of other species are represented in the U. S. National Museum (462). The species so far known are: Tuditanus minimus Moodie, Erpetosaurus scidptilis Moodie, Erpetosaurus minutus Moodie. They are the first evidence of the occurrence of amphibian remains in these deposits. The Cannelton specimens are found in a thin stratum of slate which forms part of the Middle Cannelton Coal. The Cannelton slate, in which the fossils occur, forms the roof of the Middle Kittanning Coal, which is only 20 to 30 feet above the