  STRATIGRAPHIC AND GEOGRAPHIC DISTRIBUTION OF AMPHIBIA IN THE COAL MEASURES OF NORTH AMERICA. There are but four localities in North America which have furnished any notable remains of Amphibia in the Coal Measures. These are, in the order of their discovery, the deposits at the South Joggins, Nova Scotia; the Linton, Ohio, Coal Measures; the Mazon Creek, Illinois, shales; and the Cannelton slates near Cannelton, Pennsylvania. There are, however, several other localities on the continent which have furnished evidences of Amphibia in the Coal Measures. The principal one of the latter localities is doubtfully of Coal Measures age, although recent discoveries would tend to show it is such. The deposits in question, those of the Clepsydrops shales of Vermilion County, Illinois, have, heretofore, been regarded as Permian, but the discovery of similar remains in rocks of undoubted Pennsylvanian age in Pennsylvania would seem to indicate that the Illinois deposits were contemporaneous with them. Fig. 1. Map of Upper Pennsylvanian showing land and water conditions under which the Coal Measures amphibian fauna lived. It will be noted that the chief deposits which have furnished amphibian remains are on the margins of the heavily shaded areas. (After Schuchert.) Explanation of symbols: Lands are white. Water areas are lined. Formation outcrops are black or dotted. Known shore-lines are solid lines; probable ones broken. Vertical lines in middle of continent indicate Gulf marine. (a) The deposits in Vermilion County, Illinois, lie along the north bank of Salt Fork Creek, at the tip of the "Horseshoe Bend," about 2 miles south of Oakwood, Illinois. They were discovered by Dr. J. C. Winslow, of Danville, in 1875. The remains discovered by him were forwarded to Professor Cope for identification. Later the deposits were thoroughly explored by W. F. E. Gurley, and the specimens collected by him are now preserved (86) in Walker Museum, University of Chicago. In 1907, the writer, while working for the University of Chicago, in exploring the same locality, exhausted the beds so far as they could at that time be uncovered from the landslide which had overwhelmed them. The formation in which the bones occur is a soft gray or reddish shale, and it lies without any apparent stratigraphic break on shales of Pennsylvanian age. Below these shales are several feet of limestone containing invertebrates of typical Pennsylvanian facies. There are indications of at least 3 species of Amphibia in the deposits. Case (86) has indicated with doubt a fourth species. The species are: Cricotus heteroclitus Cope, (b) In 1897 Dr. Williston (607) described some fragments of Cricotus from a deposit in Cowley County, near Winfield, Kansas. There has been some dispute as to the age of the deposit, but the consensus of opinion seems to be that the beds are of approximately the same age as those of Illinois and Pennsylvania in which similar remains are found, and those deposits are looked upon as Upper Pennsylvania (Case (94), pp. 239-240). No new forms were described from Winfield, since only a few fragments were obtained. Williston referred the phalange, the fragment of a jaw, and the tooth to Cricotus heteroclitus Cope. (c) Later in the same year Williston (608) announced the discovery of a tooth of typical labyrinthodont structure from near Louisville, Kansas (plate 21, fig. 6). The tooth was accompanied by fragments of bone and was probably not far from the bed in which it was fossilized. Williston states that the remains were from the shales which are "nearly at the upper part of the Carboniferous, probably within one hundred feet of the Manhattan Limestone." (d) In 1894 Marsh (406) and earlier (1873) Mudge (490) described footprints of vertebrates from the stone-quarries near Osage City, Kansas. The stone in which they were found was a fine-grained limestone which occurs near the middle of the Kansas Coal Measures. (e) Two years later Marsh (407) announced the discovery of traces of the oldest known (Devonian) air-breathing vertebrate. The footprints of Thinopus antiquus were regarded by Marsh as "apparently amphibian." This still remains the oldest geological evidence of air-breathing vertebrates, although Lohest some years ago (381) called attention to remains from the Devonian of France which he thought might be amphibian. The footprint described by Professor Marsh was "found in the town of Pleasant, one mile south of the Allegheny River, Warren County, Pennsylvania, by Dr. Charles E. Beecher, who presented it to Yale Museum, and also furnished the information in regard to its geological position.... The geological horizon is near the top of the Chemung, in the upper Devonian. In the same beds are ripple marks, mud cracks, and impressions of rain drops, indicating shallow water and shore deposits." (f) Among the collections of the American Museum there is an impression of a small amphibian foot obtained from Phoenix Tunnel, Pennsylvania. The impression is in hard black slate very similar to the slate of the Cannelton region. It is possible that the specimen may have been obtained from the Cannelton beds, since they would be expected to occur at Phoenix Tunnel. The impression is rather small. It is the footprint of a 5-toed animal, probably of the right foot, since no amphibian (465) so far is known from the Coal Measures with 5 digits on the hand. The first digit is short and thick, with a large ball at its base. The foot measures from the posterior edge of the palm to the tip of the longest digit 12 mm. The length of the first digit is 7 mm. The impression differs in some respects from the impressions so far known from the Coal Measures, but no attempt will be made to assign it to a Fig. 2. Distribution of Coal Measures Amphibia in North America. 1. Linton, Ohio, near Yellow Creek P. O., Jefferson County, Ohio, on the banks of Yellow Creek, near the Ohio River, 16 miles north of Steubenville. 2. Mazon Creek shales, Grundy County, Illinois, near Morris. 3. "Clepsydrops shales," Salt Fork Creek, Vermilion County, Illinois, near Oakwood, on Tate farm, 8 miles west of Danville, Illinois. 4. Danville, Illinois, coal where the type of Proterpeton gurleyi Moodie was found. 5. Breeze, Illinois, where Dr. J. A. Udden, in 1907, found a fragment of an amphibian phalange on the dump of the Cooperative Coal Company. 6. Pitcairn, Pennsylvania, 15 miles east of Pittsburgh. 7. Cannelton, Pennsylvania, Beaver County, Cannelton slates, Kittanning formation, 45 miles northwest of Pittsburgh. 8. Fairfield, Iowa, where Dr. J. A. Udden found remains attributed by Dr. Eastman to Pleuroptyx clavatus Cope. 9. Louisville, Pottawatomie County, Kansas, where Dr. S. W. Williston discovered remains of Mastodonsaurus in the Coal Measures. 10. Washington County, Kansas, source of type of Eobaphetes kansensis Moodie, from the Coal Measures. 11. Osage City, Osage County, Kansas, amphibian footprints from the Coal Measures. 12. Winfield, Kansas, source of Cricotus material. 13. Lander, Wyoming, in Wind River Carboniferous. 14. Pictou, Pictou County, Nova Scotia, 84 miles northeast of Halifax. Source of Baphetes planiceps Owen. 15. Joggins (Joggins Mines), Cumberland County, Nova Scotia, 4 miles from River Hebert. Source of Hylerpeton and Dendrerpeton faunas. 16. South Joggins, Nova Scotia, source of the Eosaurus acadianus Marsh. (g) Dr. J. A. Udden, in 1907, discovered a fragment of a phalanx of some amphibian (plate 22, fig. 3) on the dump of the Cooperative Coal Company, a mile east of Breeze, Illinois. It was obtained from below the Shoal Creek limestone and somewhere above the (Illinois) Coal No. 6, according to Dr. Udden's notes. The maximum width of the phalanx is 10 mm. and it probably had a length of 16 mm. (h) Mr. N. H. Brown, in 1914, discovered in the Carboniferous rocks to the east of the Wind River Mountains, near Lander, Wyoming, a single fragment of an amphibian. The writer was accompanying Mr. Brown at the time of the discovery and there can be no doubt that the fragment was amphibian; the location of the beds was such that no later age than the Coal Measures can be assigned to them. (i) Dr. J. A. Udden (577), in 1912, announced the discovery of an amphibian in the Des Moines formation of Iowa. These remains were identified by Dr. Charles Eastman as Pleuroptyx clavatus Cope. Since the Des Moines is probably nearly contemporaneous with the Mazon Creek shales of Illinois, the discovery does not extend the geological range to any extent, but is of interest as it adds another note to our knowledge of the geographical distribution of the Amphibia in the Coal Measures. (j) The Gurley collection of the University of Chicago possesses a single cervical vertebra of some amphibian (?). The vertebra is unlike anything previously described and represents a new form (plate 22, fig. 2) which may be designated Proterpeton gurleyi, new genus and species. The material was collected near Danville, Illinois. (k) Deposits have been discovered in Pennsylvania in which are found the remains of amphibians and reptiles, very similar to those from Vermilion County, Illinois, Cowley County, Kansas, and the Texas Permian. The remains (plate 18, fig. 2) were found in a thin stratum below the "Ames" limestone, and are therefore in the Coal Measures, fairly well below the top. The fossils, as described by Case (94), consist of fragments which he ascribes to pelycosaurian reptiles and to temnospondylous amphibians. The genus Eryops (94) is recognized in several fragments and a nearly complete dorsal vertebral centrum. Other types of Amphibia are likewise represented. (l) The ironstone nodules, in which the Mazon Creek fossils (plate 1) occur, are found in the shale which forms the roof of the Morris or "No. 2" Coal of Illinois, which "lies probably somewhat lower than the horizon of the Lower Kittanning Coal of Pennsylvania" (599). "The nodules of iron contained in the Coal shales on the banks of Mazon Creek near Morris, Illinois, generally contain organic nuclei, and thousands of beautiful specimens have been obtained there. They are usually fragments of fern fronds, but are sometimes shells, crustaceans, myriapods, scorpions, spiders, cockroaches, ... fishes" (498, p. 214), and amphibians, of which 10 species are at present known. MOODIE VIEWS ALONG MAZON CREEK, ILLINOIS. 1. A nodule weathering out of the shale, at the head of the hammer. Most of the nodules at the so-called "lower beds" contain specimens of Neuropteris. 2. The nodules in the creek bed at the "upper beds." Many of them have been cracked open by the frost. 3. Looking south at the "upper beds." The nodules found in the background are non-fossiliferous. 4. Nodules may be seen through the clear water embedded in the shale. Neuropterid insects in the water. 5. Looking for nodules at the "upper beds." The uppermost reaches of the fossiliferous beds correspond with the extreme background of the picture. 6. Nodules in the stream bed at the "lower beds." Many of these are cracked open by the frost and good specimens are sometimes found in the nodules. These species have been arranged zoologically according to the following plan: Class Amphibia LinnÉ, 1758. It will be seen from the above arrangement that nearly all of the orders of Amphibia are represented in the Mazon Creek fauna. These animals are the oldest known land vertebrates of North America. Fig. 3. Portion of the "Morris sheet" of the U. S. Geological Survey, to show topography and situations of the exposures of fossil-bearing shales at Mazon River, a, the "Bartlett place," the so-called "upper beds"; b, "lower beds." The writer was able, during July 1911, to spend a week studying the fossil beds (479) at Mazon Creek. The object of the visit was primarily to collect Amphibia, but although several thousand nodules were examined, not one contained an amphibian nor a fragment of one. Mr. J. C. Carr, of Morris, Illinois, who has collected at Mazon Creek for more than 30 years, has never collected an amphibian. These facts interested me in making the following comparison: If we take 100,000 nodules as a basis for computation of the rarity of the various forms, something like the following will be the approximate result of the investigation: Of 100,000 nodules, 20,000 will be barren or contain only indeterminate fragments; 68,500 will contain plants; 7,500 will contain insects, Crustacea, myriapods, scorpions, spiders, and other arthropods; 3,900 will contain fish coprolites or scales; 95 may contain fish or fragments of fish; 4 may contain mollusks; and 1 may contain an amphibian or a fragment of one. Perhaps even 100,000 is low as a basis of estimate. Mr. Carr was of the opinion that 1 nodule in every 500,000 might contain an amphibian. The beds from which the nodules are usually collected occur along both banks and in the bottom of the creek, in two localities. One locality known as the Bartlett place is situated 8 miles southeast of Morris, in Grundy County, Illinois, Wauponsee Township, N.W. quarter, section 30, Township 33, Range 8, the land being now owned by Mrs. Emma Akerly, of Wilmington, Illinois. The fossil-bearing nodules occur throughout 6 to 8 feet of shale along both banks of the creek at the "upper beds" (plate 1, fig. 3), as the Bartlett place is called. They may also be seen in the bed of the creek, when the water is low (plate 1, fig. 4), still embedded in the shale. With a potato fork the shale is easily turned and the nodules come out like potatoes. One sometimes finds a "pocket" of nodules from which as many as a peck may be secured. Nearly every nodule has a fossil at the "upper beds," but all of the fossils are not well preserved, possibly only 1 or 2 out of every 10 being worth carrying to the museum. The nodules crack best when wet, and it requires some skill to crack them evenly. They seem quite light and, in one place where the stream curves, are piled in a long windrow. On this were found, in nodules cracked by the frost, several good crustaceans and many good plants. Table of Pennsylvanic Formations. Series Northern Appalachian. Bituminous. The fossils at the "upper beds" are localized into special strata. At one place in the upper part of the deposit, in a reddish shale, one finds that insects are more abundant than they are lower down. The Crustacea seem to come from apparently the same shale. At the lower end of the deposit certain definite species of Pecopteris are localized. It is an interesting fact that one seldom finds a Neuropteris at the "upper beds." The most abundant fossils are the various species of Pecopteris and Annularia. When specimens of Neuropteris are found they are usually discovered at the lower end of the exposures. In one place behind the "island" very blue nodules, hard and flinty and with sometimes well-preserved At the "lower beds" (plate 1, 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 Amphibamus 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. (m) 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 sculptilis 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 (n) The Linton, Ohio, beds outcropped near Linton post-office, which was formerly located at the mouth of Yellow Creek, a few hundred yards from the present station, Yellow Creek, Salem Township, Jefferson County, in the valley of Yellow Creek, near the Ohio River, and thus near the Pennsylvania state line. In regard to the exact location of the town of Linton, which has long since been abandoned, I quote from a letter from Dr. Louis Hussakof, who visited the locality: "The locality appears to have been known as Yellow Creek for many years past. That is the name used in the Geological Map of Ohio published by Orton in 1888 and which was based on the earlier maps of Newberry (1869 and 1879). When I visited the place in 1905, and asked for Linton (which I had not been able to locate on any map then available to me), hardly anyone knew of such a locality. Only one old man in Steubenville, Ohio, recalled that Yellow Creek was identical with Linton. "Yellow Creek is not a village, but only a R. R. station (on the Pennsylvania R. R.), and marks a spot where once was an active and prosperous mine. Probably at a former day there was a small post-office somewhere in the neighborhood known as Linton. I did not take any photographs, as I was not certain of the spot, or the mine, from which the fossils had come. There are some cement mines within a few minutes' walk of the station, but no coal appears to be mined at present at Yellow Creek. 'Smith's Pit,' the coal mine best remembered by the younger men, is not worked. "Now as to the question whether some of the Amphibia might have come from localities in Columbiana County. I believe it very probable that they did. I walked along the road from Yellow Creek (Jefferson County) to Wellsville (Columbiana County), a distance of about 2 or 2.5 miles, and the country seemed quite the same. Everywhere one sees outcrops of coal in the cuts along the road. Furthermore, I inclose a copy of a page in an old notebook of Professor Newberry from which you will see that Coal Measure fossil localities were known not only at Yellow Creek, but also from near Wellsville. There can be hardly a doubt that most of the specimens you have are from Yellow Creek; and quite a number are those collected by Sam Huston." Newberry says, in regard to the fauna of the Linton Coal: "The Linton locality is especially interesting and instructive. It has already (1889) yielded more than 20 species of fishes and nearly 40 species of aquatic amphibians, all inhabitants of the same body of water. These were found in a thin stratum of cannel which, over a limited area, underlies a thick bed of cubical coal (No. 6 of the Ohio reports), of which the place is near the top of the Lower Coal Measures. At Linton, ... we have evidence that the great marsh in which the peat accumulated that formed coal No. 6 was for a time a lake or a lagoon, inhabited by the fishes and amphibians to which I have referred.... Many of the fishes and the amphibians were highly carnivorous and powerful, as we learn from their teeth and coprolites. The largest of the amphibians must have been 8 or 10 feet in length, having strong jaws, set with numerous lancet-shaped teeth an inch or more in length.... After a sufficient time had elapsed for many generations of fishes and aquatic salamanders to live and die, the lake was filled by the extension of its peaty shores into it just as so many lakelets are filled and obliterated at the present time and afterward over the cannel was formed a mass of peat, which has now become a stratum of cubical coal 7 feet in thickness. "In the Linton cannel are buried fragments or entire individuals of all the inhabitants of this body of water which had hard parts, bones, scales, spines, or teeth, capable of preservation. Hence we get a locally complete picture of the life of the Carboniferous age, and we find it to be unexpectedly rich and varied. In that age fishes and amphibians were the highest forms of animal life, and the amphibians were comparatively newcomers on the earth's surface. Yet they had multiplied and differentiated until this little pool contained millions of them, varying in length from 6 inches to 10 feet and curiously diversified in their forms, their scales, and spines, and in the ornamentation of their enamel-covered heads" (498). "To the paleontologist there are few places in the world more interesting than the Diamond mine, at Linton, since here we get such a view of the life of the Carboniferous age as is afforded almost nowhere else, and of the great numbers of species found there, not more than three or four have been met with elsewhere" (497). On page 18 is a list of the Amphibia which are thus far described from the Linton deposits. They all belong, so far as known, to the Microsauria, the reference of any of the species to other orders being doubtful. The larger Amphibia seem to be indicated by a large rib which resembles very much that described by Huxley in 1863 for Anthracosaurus. Amphibia from the Linton Beds (51 SPECIES). Brachydectes newberryi Cope. Fragment of a skull. Besides the above-listed species there are others indicated by fragments too poorly preserved to be worthy of specific designation. The Linton Amphibia are all apparently confined exclusively to that locality. Species from the Cannelton slates have been assigned, however, to genera which occur at Linton, i.e., Erpetosaurus and Tuditanus. This reference may be due to lack of knowledge, as the forms are insufficiently known. A single Linton species has been assigned to Ichthyerpeton, a genus (o) The deposits in Nova Scotia have been correlated with the Coal Measures strata of the United States (Bell, Summ. Rpt. Geol. Surv. Canada, 1912, 1914, 360-371). They are very near the same age as the Linton beds and come in near the base of the Allegheny River series. The exposures are at the South Joggins, along the sea-coast. Here in strata of clay interstratified with coal are found the erect stumps of the SigillariÆ, and it was in the rock within these stumps that Lyell and Dawson, in 1853, discovered the remains of the amphibians which they termed "reptiles." "The bones of Dendrerpeton hitherto found, as well as those of the smaller species, have been obtained from the interior of erect SigillariÆ, and all of those in one of the many beds which, at the Joggins, contain such remains. The thick cellular inner bark of the Sigillaria was very perishable; the slender woody axis was somewhat more durable; but near the surface of the stem, there was a layer of elongated cells, or bast tissue of considerable durability, and the outer bark was exceedingly dense and indestructible. Hence an erect tree, partly imbedded in sediment, and subjected to the influence of the weather, became a hollow shell of bark. When they remained open for a considerable time, they would constitute pitfalls into which animals walking on the surface might be precipitated. When the surface was inundated all such remains would be covered and imbedded in the sediment. These seem to have been the precise conditions of the bed which afforded these remains." (Dawson, 223, 1894.) Fifteen species have been described from the Joggins deposits. Two are known from the Albion mines, south Nova Scotia, where were obtained the remains of Baphetes planiceps Owen and B. minor Dawson. The following 17 species of Amphibia are known from the Carboniferous of Canada: Amblyodon problematicum Dawson. Teeth and fragments. (p) All the remains representing the above species were collected by Sir J. William Dawson at the South Joggins and at the mines of Albion, with the exception of Eosaurus, which was collected by O. C. Marsh. The collections of Dawson are now in the Peter Redpath Museum of McGill University in Montreal and in the British Museum of Natural History at South Kensington, London. The history of the discovery of the deposits and their amphibian fossils at the South Joggins is so interesting that it was thought worth while to reproduce in large part Dawson's paper "On the Mode of Occurrence of Remains of Land Animals in Erect Trees at the South Joggins, Nova Scotia," published in 1891 in the Transactions of the Royal Society of Canada, section IV, p. 127: "The remarkable section of coal-formation rocks at the South Joggins, in Cumberland County, has long been known as one of the most instructive in the world; exhibiting as it does a thickness of 5,000 feet of strata of coal-formation in a cliff of considerable height, kept clean by the tides and waves, and in the reefs extending from this to the shore, which at low tide expose the beds very perfectly. It was first described in detail by the late Sir W. E. Logan (Report Geol. Surv. Canada, 1844), and afterwards the middle portion of it was still more detailed by the author (Dawson), more especially in connection with the fossil remains characteristic of the several beds and the vegetable constituents and accompaniments of the numerous seams of coal (Jour. Geol. Soc. Lond., X, p. 1, 1853). It was on occasion of a visit of the author in company with Sir Charles Lyell, and in the pursuit of these investigations, that one of the most remarkable features of the section was disclosed in 1851. This is the occurrence, in the trunks of certain trees imbedded in an erect position in the sandstones of Coal-mine Point, of remains of small reptiles, which with one exception, a specimen from the Pictou coal-fields, were the first ever discovered in the Carboniferous rocks of the American continent, and are still (1891) the most perfect examples known of a most interesting family of coal-formation animals, intermediate in some respects between reptiles proper and batrachians, and known as Microsauria. With these were found the first-known Carboniferous land snails and millipedes. Very complete collections of these remains have been placed by the author with his other specimens in the Peter Redpath Museum and in the British Museum. "A forest or grove of the large ribbed trees known as SigillariÆ was either submerged by subsidence or, growing on low ground, was invaded with the muddy waters of an inundation, or successive inundations, so that the trunks were buried to the depth of several feet. The projecting tops having been removed by subaerial decay, the buried stumps became hollow, while their hard outer bark remained intact. They thus became hollow cylinders in a vertical position and open at the top. The surface having then become dry land, covered with vegetation, was haunted by small quadrupeds and other land animals, which from time to time fell into the open holes, in some cases nine feet deep, and could not extricate themselves. On their death, and the decomposition of their soft parts, their bones and other hard portions remained in the bottom of the tree intermixed with any vegetable debris or soil washed in by rain, and which formed thin layers separating successive animal deposits from each other. Finally, the area was again submerged or overflowed by water, bearing sand and mud. The hollow trees were filled to the top and their animal contents thus sealed up. At length the material filling the trees was by pressure and the access of cementing matter hardened to stone, not infrequently harder than that of the contained beds, and the whole being tilted to an angle of 20°, and elevated into land exposed to the action of the tide and waves, these singular coffins present themselves as stony cylinders projecting from the cliff or reef, and can be extracted and their contents studied. The singular combination of accidents above detailed was, of course, of very rare occurrence, and, "There is evidence in coprolitic matter on one of the surfaces within the trunks, and also in certain trails on these surfaces, that some of the imprisoned animals lived for a time in their subterranean prisons; that they crept around their walls in search of a way of escape, and that the larger animals fed on smaller species entrapped along with them." Fig. 5. Dawson's tree No. 13 at the South Joggins, Nova Scotia. Upper part, in situ, in the reef after it had been exposed by blasting. (After Dawson, based on a photograph.) After the discovery of these entombed amphibians Sir William Dawson was given a grant of £50 from the Government Fund by the council of the Royal Society of London, to aid in the extraction of these trees and the collection of their contents. The trees were carefully taken out and their contents examined; the portions containing the animal remains were carefully boxed to be taken to Montreal for final cleaning and study. Erosion goes on rapidly at the South Joggins, but no one has paid any attention to the occurrence of Amphibia along the coast of Nova Scotia within recent years. (q) A deposit which will be of undoubted interest in connection with the occurrence of Amphibia in the Coal Measures is that which outcrops along the banks of Rock Creek in the South western part of Douglas County, Kansas, in Marion Township (Township 14 south, Range 18 east, SW. and SE. quarters of section 7), about 2 miles from the now-abandoned post-office of Twin Mounds, so called from the two flat-topped, elongated mounds of Oread limestone to the west of the town. The interest in these beds is not due to the discovery of Amphibia in them, but the possibilities of such discoveries. This is indicated by the occurrence of fossils, in nodules similar to those obtained from Mazon Creek, which are identical generically, nd in most cases specifically, with the Mazon Creek animals and plants. The fossils so far collected from this interesting locality are:
The fossils occur in definite strata of nodules immediately above a 10-inch coal seam which is worked for local consumption. The coal lies near the base of the exposure in the more western portion of the outcrop, but it is raised by an anticlinal fold to near the top of the creek-banks by the bridge across Rock Creek, along the banks of which the shales are exposed. Nodules containing fossils are found most abundantly at the western exposure on the McKinzie place, only a few having been found near the bridge. Below the coal-seam, nodules of various shapes and sizes occur, but they seldom contain fossils and never good ones. Occasionally, as at Mazon Creek, fragments of plants adhere to the outside of the incrusting shale. A single nodule may have adhering to it fragments of 4 genera of plants. The fossiliferous nodules all occur above the coal and are most prolific and abundant immediately above the seam, within the first 10 inches. In the same stratum of shale with the nodules are found abundant impressions of plants in the shale, often perfect fronds being uncovered. (See, in this connection, Twenhofel and Dunbar, 1914, "Nodules with Fishes from the Coal Measures of Kansas," Amer. Journ. Sci., XXXVIII, pp. 157-163.) G. F. Matthew (408-413) has described numerous genera and species of footprints, presumably amphibian, from the Carboniferous of Canada. The impressions indicate small creatures for the most part. Other imprints have been described by Logan, Dawson, Lyell, Marsh, Mudge, and Lea. Since the present work is intended largely for a morphological review, only passing notice can be given to the ichnites. The literature on the "Ichnites" has been brought together in Hay's "Bibliography and Catalogue of Fossil Vertebrata of North America," pp. 538-553. References since the publication of Hay's catalogue (317) will be found in the bibliography at the end of this work. Footprints are of interest in that they are the only evidence we have of the occurrence of land vertebrates in the Devonian and Mississippian of North America. |
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