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SIR" 
 
 UY Of 
 CALIFORNIA 
 
 UNIVERSITY OF CALIFORNIA. 
 
 FROM THE LIBRARY OF 
 
 DR. JOSEPH LECONTE. 
 
 GIFT OF MRS. LECONTE. 
 
 EARTH 
 SCIENCES 
 JJBBABX 
 
 No. 
 
AIR-BREATHERS 
 
 OF THE 
 
 COAL PERIOD 
 
 A DESCRIPTIVE ACCOUNT OF TH REMAINS OF LAND ANIMALS 
 FOUND IN THE COAL FORMATION 
 
 OF 
 
 NO A' A SCOTIA 
 
 WITH REMARKS ON THEIR BEARING ON THEORIES OF THE FORMATION OP 
 COAL AND OF THE ORIGIN OF SPECIEP, 
 
 BY J. W. DAWSON, LL.D., F.R.S., F.G.S., ETC., 
 
 principal of |Rc6ill KmbmHi?, 
 
 WITH ILLUSTKATIONS 
 
 DAWSON 3 BROTHERS, GREAT ST. JAMES STREET, 
 
 LONDON, H. BAILLIERE ; NEW YORK, BAILLIERE, BROTHERS. 
 1863. 
 
OF THE 
 
 UNIVERSITY 
 
 OF 
 
AIR-BREATHERS OF THE COAL PERIOD, 
 
 IF 
 
AIR-BREATHERS 
 
 OP THE 
 
 COAL PERIOD: 
 
 A DESCRIPTIVE ACCOUNT OF THE REMAINS OP LAND ANIMALS 
 FOUND IN THE COAL FORMATION 
 
 OP 
 
 NOVA SCOTIA, 
 
 WITH REMARKS ON THEIR BEARING ON THEORIES OP THE FORMATION OF 
 COAL AND OF THE ORIGIN OF SPECIES. 
 
 BY J. W. DAWSON, LL.D., F.R.S., F.G.S., ETC., 
 
 inHpal flf gftc&ill Winiijtriiiy. 
 
 WITH ILLUSTRATIONS. 
 
 t)AWSON BROTHERS, GREAT ST. JAMES STREEf . 
 
 LONDON, H. BAILLIERE J NEW YORK, BAILLIERE BROTHERS. 
 1863. 
 

 -J33 
 
 EARTH 
 SCIENCES 
 LIBRARY 
 
CONTENTS. 
 
 PAGES. 
 
 1 INTRODUCTORY, 1 
 
 2 FOOTPRINTS, 5 
 
 3 BAPHETES PLANICBPS, 10 
 
 4 DBNDRERPETON ACADIANUM, 17 
 
 5 DENDRERPETON OWBNI, 32 
 
 6 REMAINS OF SKIN AND SCALES, 34 
 
 7 HYLONOMUS LTELLI, 40 
 
 8 HYLONOMUS ACIBDBNDATDS, 49 
 
 9 HYLONOMUS WYMANI, 52 
 
 10 HYLBRPETON DAWSONI, 55 
 
 11 OTHER REPTILIAN REMAINS, 58 
 
 12 INVERTEBRATE AIR-BREATHERS, 62 
 
 13 CHARACTERS OF THE ANIMALS DESCRIBED, 65 
 
 14 CONCLUDING REMARKS, 68 
 
PKEFACE. 
 
 A certain moral obligation rests on the discoverer or pos- 
 sessor of new and valuable fossils, to make them known as 
 extensively as possible to the scientific world. This he may 
 do either personally or by the aid of others more conversant 
 with the class of objects in question. I have generally pre- 
 ferred the latter course for all objects not included in my 
 own special lines of investigation ; and in the case of the 
 subjects of the present brochure ^have presented them, as dis- 
 covered, to the investigation of naturalists specially engaged 
 in the study of such remains. Through their kindness my 
 specimens have been extensively illustrated, chiefly in the 
 pages of the Journal of the Geological Society of London. 
 I have, however, found it impossible to bring out in this way 
 all the details desirable, and to present a connected view of 
 the facts. Hence the present publication, in which I give a 
 summary of all that I have been able to ascertain of the land 
 animals of the coal period in Nova Scotia, and endeavour to 
 make my collection of their fossil remains the common pro- 
 perty of all geologists and naturalists, thereby discharging 
 the obligations under which I am laid by having had these 
 precious relics placed by Providence in my hands. 
 
IV PREFACE. 
 
 To do this has cost me some sacrifice. The time required 
 has been snatched from scanty intervals of rest in the midst 
 of daily severe toil, and above all it has necessarily been 
 taken from the prosecution of those researches in the fossil bo- 
 tany of the palaeozoic period, to which I have devoted special 
 attention for many years, and which are yet very incomplete. 
 These circumstances, and the scanty means of reference and 
 comparison at my disposal, I must plead as excuses for any 
 imperfections which may appear in the work. 
 
 The lithographed illustrations must not be taken as evi- 
 dence of the state of art in Canada. They are merely trans- 
 fers from my own rough tracings of the objects, and the only 
 merit which they claim is that of accuracy of outline. 
 
 The photograph inserted in some of the copies, I owe to 
 the kindness of Mr. G. R. Prowse, an amateur artist of this 
 city. It presents an accurate magnified picture of some 
 of the principal remains ; and deserves much praise as a 
 highly successful application of microscopic photography to 
 very difficult objects. 
 
 It is proper to add that the greater part of the matter of 
 this memoir has appeared in the Canadian Naturalist and 
 Geologist for 1863. 
 
 J. W. DAWSON. 
 
 McGiLL UNIVERSITY, MONTREAL, 
 Jnne, 1863. 
 
THE AIR-BREATHERS 
 
 OF THE 
 
 COAL PERIOD 
 
 IN 
 
 NOVA SCOTIA. 
 
 L INTRODUCTORY. 
 
 The animal population of the earth during the older or palaeo- 
 zoic period of its geological history, is known to us chiefly through 
 the medium of remains preserved in rocks deposited in the bed of 
 the ocean. In such rocks we have little reason to expect an 
 abundant representation of the animals of the land, even if these 
 existed at the time plentifully on the neighbouring shores. Per- 
 haps for this reason, perhaps because there were then no land 
 animals, the organic remains of the Cambrian, Silurian, and Lower 
 Devonian rocks consist, in so far as animal life is concerned, 
 solely of marine species. In the Upper Silurian and Lower De- 
 vonian, however, land plants begin to appear ; and in the Upper 
 Devonian these are so numerous and varied as to afford a proba- 
 bility that animals also tenanted the land. Indeed, Mr. Hartt, of 
 St. John, has just announced the discovery of remains, which he be- 
 lieves to be attributable to insects, in the rich pi ant-bearing Upper 
 Devonian beds of that locality.* It is true also that reptiles of 
 
 * In a letter to the author. It is to be hoped that descriptions of these 
 interesting remains may soon be published. 
 
2 AIR-BREATHERS OF THE COAL PERIOD. 
 
 ,-v 
 
 high organization have been found in beds referred to the UppwP 
 Devonian, at Elgin, in Scotland ; bat so much doubt rests on the 
 age of these beds, that it is unsafe at present to regard them as 
 affording evidence of reptilian life at so early a period. 
 /// That there was dry land, even in the Lower Silurian period, we 
 know, and can even trace its former shores. In Canada our old 
 Laurentian coast extends for more than a thousand miles, from 
 Labrador to Lake Superior, marking the southern border of the 
 nucleus of the American continent in the Lower Silurian period. 
 Along a great part of this ancient coast we have the sand-flats of 
 the Potsdam Sandstone, affording very favorable conditions for 
 the imbedding of land animals, did these exist ; still, notwithstand- 
 ing the zealous explorations of the Geological Survey, and of 
 many amateurs, no trace of an air-breather has been found. I 
 have myself followed the Lower Silurian beds up to their ancient 
 limits in some localities, and collected the shells which the waves 
 had dashed on the beach, and have seen under the Silurian 
 beds, the Laurentian rocks pitted and indented with weather 
 marks, showing that this old shore was then gradually subsiding ; 
 yet the record of the rocks was totally silent as to the animals 
 that may have trod the shore, or the trees that may have waved 
 over it. All that can be said is that the sun shone, the rain fell, 
 and the wind blew as it does now, and that the sea abounded in 
 living creatures. The eyes of trilobites, the weathered Lauren- 
 tiau rocks, the wind-ripples in the Potsdam sandstone, the rich 
 fossils of the limestones, testify to these things. The existence 
 of such conditions would lead us to hope that land animals may 
 yet be found in these older formations. On the other hand, the 
 gradual failure of one form of life after another, as we descend in 
 the geological series, and the absence of fishes and land plants in 
 the older Silurian rocks, might induce us to believe that we have 
 here reached the beginning of animal life, and have left far behind 
 us those forms that inhabit the land. 
 
 Even in the Carboniferous period, though land plants abound, 
 air-breathers are few, and most of them have only been recently 
 
AIR-BREATHERS OP THE COAL PERIOD. 3 
 
 recognized. We know, however, with certainty that the dark 
 and luxuriant forests of the coal period were not destitute of ani- 
 mal life. Reptiles crept under their shade, land-snails and milli- 
 pedes fed on the rank leaves and decaying vegetable matter, and 
 insects flitted through the air of the sunnier spots. Great interest 
 attaches to these creatures; perhaps the first-born species in some 
 of their respective types, and certainly belonging to one of the 
 oldest land faunas, and presenting prototypes of future forms 
 equally interesting to the geologist and the zoologist. 
 
 It has happened to the writer of these pages to have had some 
 share in the discovery of several of these ancient animals. The 
 coal formation of Nova Scotia, so full in its development, so rich in 
 fossil remains, and so well exposed in coast cliffs, has afforded ad- 
 mirable opportunities for such discoveries, which have been so far 
 improved that at least eight out of the not very large number of 
 known Carboniferous land animals, have been obtained from it.* 
 The descriptions of these creatures, found at various times and at 
 various places, are scattered through papers ranging in date from 
 1844 to!862,f and are too fragmentary to give complete informa- 
 tion respecting the structures of the animals, and their conditions 
 of existence. I have, for some time, designed to prepare a 
 resume* of the published facts, with the addition of such new points 
 as may arise from the further study of the specimens, but have 
 been deterred by the incomplete state of my knowledge, and the 
 prospect of further discoveries. So much has, however, now been 
 done, and so many difficulties have been removed by the labours 
 of several eminent naturalists who have examined the specimens, 
 that I think the time has arrived when such a work may be under- 
 taken with advantage to science. 
 
 * It appears that five species of Carboniferous reptiles have been re- 
 cognised on the continent of Europe, three in Great Britain, and four in 
 the United States. More full references will be made to these in the 
 sequel. 
 
 t Papers by Lyell, Owen, and the author, in the Journal of the Geolo- 
 gical Society of London, vols. i, ii, ix, x, xi, xvi, xvii, xviii. 
 
4 AIR-BREATHERS OF THE COAL PERIOD. 
 
 In now endeavouring more fully to introduce the tenants of the 
 coal forests of Nova Scotia to the notice of geologists and of the 
 general reader, I shall take them nearly in the order in which 
 they have become known to me, and shall not scruple to indulge 
 in some gossip as to the circumstances of their discovery, and in 
 some speculations as to their modes of life. I shall however endeav- 
 or carefully to sum up the facts ascertained as to their structure, 
 and their relation to other creatures, whether their contemporaries 
 or successors. 
 
AIR-BREATHERS OF THE COAL PERIOD. 
 
 II. FOOTPRINTS. 
 Plate I. 
 
 It has often happened to geologists, as to other explorers of 
 new regions, that footprints on the sand have guided them to the 
 inhabitants of unknown lands. The first trace ever observed of 
 reptiles in the carboniferous system, consisted of a series of small 
 but well-marked footprints found by Sir W. E. Logan, in 1841, 
 in the lower coal measures of Horton Bluff, in Nova Scotia ; and 
 as the authors of all our general works on geology have hitherto, 
 in so far as I am aware, failed to do justice to this discovery, I 
 shall notice it here in detail. In the year above mentioned, Sir 
 William, then Mr. Logan, examined the coal fields of Pennsylvania 
 and Nova Scotia, with the view of studying their structure, and ex- 
 tending the application of the discoveries as to Stigmaria under- 
 clays which he had made in the Welsh coal fields. On his return 
 to England, he read a paper on these subjects before the Geologi- 
 cal Society of London, in which he noticed the discovery of rep- 
 tilian footprints at Horton Bluff. The specimen was exhibited 
 at the meeting of the Society, and was, I believe, admitted on the 
 high authority of Prof. Owen, to be probably reptilian. Unfortun- 
 ately, Sir William's paper appeared only in abstract in the Trans- 
 actions ; and in this abstract, though the footprints are mentioned, 
 no opinion is expressed as to their nature. Sir William's own 
 opinion is thus stated in a letter to me, dated June, 1843, when 
 he was on his way to Canada, to commence the survey which has 
 since developed so astonishing a mass of geological facts. 
 
 " Among the specimens which I carried from Horton Bluff, one 
 is of very high interest. It exhibits the footprints of some reptilian 
 animal. Owen has no doubt of the marks being genuine footprints. 
 The rocks of Horton Bluff are below the gypsum of that neigh- 
 bourhood ; so that the specimen in question (if Lyell's views are 
 
6 AIR-BREATHERS OF THE COAL PERIOD. 
 
 correct*) comes from the very bottom of the coal series, or at any 
 rate very low down in it, and demonstrates the existence of reptile s 
 at an earlier epoch than has hitherto been determined ; none having 
 been previously found below the magnesian limestone, or to give it 
 Murchison's new name, the * Permian era.' " 
 
 This extract is of interest, not merely as an item of evidence in 
 relation to the matter now in hand, but as a mark in the progress 
 of geological investigation. For the reasons above stated, the im- 
 portant discovery thus made in 1841, and published in 1842, was 
 overlooked ; and the discovery of reptilian bones by Von Dechen, 
 at Saarbruck, in 1844, and that of footprints by Dr. King in the 
 same year, in Pennsylvania, have been uniformly referred to as the 
 first observations of this kind. This error I now desire to correct, 
 not merely in the interest of truth, but also in that of my friend Sir 
 William Logan, and of my native province of Nova Scotia ; and 
 I trust that henceforth the received statement will be, that the first 
 indications of the existence of reptiles in the coal period, were ob- 
 tained by Logan, in the lower coal formation of Nova Scotia, in 
 1841. Insects and arachnidans, it may be observed, had pre- 
 viously been discovered in the coal formation in Europe. 
 
 The original specimen of these footprints is still in the collec- 
 tion of Sir William Logan. It is a slab of dark colored sand- 
 stone, glazed with fine clay on the surface ; and having a series of 
 seven footprints in two rows, distant about 3 inches ; the distance 
 of the impressions in each row being 3 or 4 inches, and the individual 
 impressions about 1 inch in length. They seem to have been made 
 by the points of the toes, which must have been armed with strong 
 and apparently blunt claws, and appear as if either the surface had 
 been somewhat firm, or as if the body of the animal had been 
 partly water-borne. In one place only is there a distinct mark of 
 the whole foot, as if the animal had exerted an unusual pressure 
 
 * Sir Charles Lyell bad then just read a paper announcing his discovery 
 that the gypsiferous system of Nova Scotia is Lower Carboniferous, in 
 which he mentions the footprints referred to, as being reptilian. 
 
AIR-BHEATHERS OF THE COAL PERIOD. 7 
 
 in turning or stopping suddenly. One pair of feet, the fore feet I 
 presume, appear to have had four claws ; the other pair may have 
 had three or four, and it is to be observed that the outer toe, as in 
 the larger footprints discovered by Dr. King, projects in the man- 
 ner of a thumb, as in the cheirotherian tracks of the Trias. No mark 
 of the tail or belly appears. The impressions are such as may have 
 been made by some of the reptiles to be described in the sequel, 
 as, for instance, by Dendrerpeton Acadianum. 
 
 Attention having been directed to such marks by these obser- 
 vations of Sir William Logan, several other discoveries of the 
 same kind were subsequently made, in various parts of the pro- 
 vince, and in different members of the carboniferous system. 
 The first of these, in order of time, was made in 1844, in 
 beds of red sandstone and shale near Tatamagouche, in the eastern 
 part of Nova Scotia, and belonging to the upper or newer mem- 
 bers of the coal measures. In examining these beds with the view 
 of determining their precise geological age, I found on the surface 
 of some of them impressions of worm-burrows, rain drops, and sun- 
 cracks, and with these, two kinds of footprints, probably of rep- 
 tilian animals. One kind consisted of marks, or rather scratches, 
 as of three toes, and resembling somewhat the scratches made by 
 the claws of a tortoise in creeping up a bank of stiff clay ; they 
 were probably of the same nature and origin with those found by 
 Logan at Horton. The others were of very different appearance. 
 They consisted of two series of strongly marked elongated impres- 
 sions, without distinct marks of toes, in series four inches distant 
 from each other, and with an intervening tail mark. They seem 
 to have been produced by an animal wading in soft mud, so thai 
 deep holes, rather than regular impressions, marked its footsteps, 
 and that in the hind foot, the heel touched the surface, giving a 
 plantigrade appearance to the tracks. Rain marks had been 
 impressed on the surface after the animal had passed over it, and 
 these had probably aided in obliterating the finer parts of the im- 
 pressions. These observations were published in the Journal of 
 the Geological Society of London, vols. 1st and 2nd. 
 
8 AIR-BREATHERS OP THE COAL PERIOD. 
 
 Shortly afterward, Dr. Harding, of Windsor, when examining 
 a cargo of sandstone which had been landed at that place from 
 Parrsboro', found on one of the slabs a very distinct series of foot- 
 prints each with four toes, and a trace of the fifth. Dr. Hard- 
 ing's specimen is now in the museum of King's College, Windsor. 
 Its impressions are more distinct, but not very different otherwise 
 from those above described as found at Horton Bluff. The rocks 
 at that place are probably of nearly the same age with those of 
 Parrsboro'. I afterward examined the place from which this slab 
 had been quarried, and satisfied myself that the beds are Carboni- 
 ferous, and probably Lower Carboniferous. They were ripple- 
 inarked and sun-cracked, and I thought I could detect trifid foot- 
 prints, though more obscure than those in Dr. Harding's slab. 
 Similar footprints are also stated to have been found by Dr. Gesner, 
 at Parrsboro'. 
 
 T have since observed several instances of such impressions at 
 the Joggins, at Horton, and near Windsor, showing that they are 
 by no means rare, and that reptilian animals existed in no incon- 
 siderable numbers throughout the coal-field of Nova Scotia, and 
 from the beginning to the end of the carboniferous period. Two of 
 the more interesting examples are figured with those already des- 
 cribed. On comparing these with one another, it will be observed 
 that Logan's, Harding's, and one of mine are of similar general 
 character, and may have been made by one kind of animal, 
 which must have had the fore and hind feet nearly of equal size. 
 The other belongs to a smaller animal, which probably travelled 
 on longer limbs, more in the manner of an ordinary quadruped. 
 Its toes cannot be distinguished. On the whole, these footprints, 
 while differing from those found by Dr. King in Pennsylvania, 
 do not prove the existence of any kind of animal distinct from 
 those to be described in the sequel, and known to us by the pre- 
 servation of portions of their skeletons. 
 
 The study of these footprints shows that the animals which 
 produced them may, in certain circumstances, have left impres- 
 sions of only 'two or three of their toes, while in other cir- 
 
AIR-BREATHERS OF THE COAL PERIOD. 
 
 cumstances all may have left marks ; and that, when wading in 
 deep mud, their footprints were altogether different from those 
 made on hard sand or clay. In some instances the impressions 
 may have been made by animals wading or swimming in water, 
 while in others the rain-marks and sun-cracks afford evidence that 
 the surface was a sub-aerial one. They are chiefly inter- 
 esting as indicating the wide diffusion and abundance of the 
 creatures producing them, and that they haunted tidal flats and 
 muddy shores, perhaps emerging from the water that they might 
 bask in the sun, or possibly searching for food among the rejecta- 
 menta of the sea, or of lagunes and estuaries. 
 
 EXPLANATION OF PLATE I. 
 Footprints of Reptiles, fyc. 
 
 Fig. 1. Footprints discovered by Sir W. E. Logan, in the Lower Car- 
 boniferous beds of Horton Bluff, in 1841 ; reduced to one- 
 fourth of the natural size, (la) one of the impressions, natu- 
 ral size. 
 
 " 2. Footprints discovered by Dr. Harding, in the Lower Carbonife- 
 rous beds of Parrsboro'; one-fourth bf the natural size. (2a) 
 Prints of fore and hind foot natural size. This figure is 
 from a rubbing kindly taken for me by Prof. How, of Wind- 
 sor. 
 
 " 3. Footprints from the Coal Measures of the South Joggins ; 
 one-fourth natural size. (3 a) One of the impressions natu- 
 ral size. 
 
 " 4.- Smaller footprints from the South Joggins ; one-fourth natu- 
 ral size. 
 
 " 5. Skin of a reptile, found with remains of a small Dendrerpeton, 
 in an erect tree at the Joggins. (a) Scaly portions ; (b) 
 Traces of hind leg? and small scales, (c) (d) Portions 
 magnified, showing scales. 
 
10 AIR-BREATHERS OF THE COAL PERIOD. 
 
 III. BAPHETES PLANICEPS. 
 Plate II. 
 
 In the summer of 1851, 1 had occasion to spend a day at the 
 Albion mines; and on arriving at the railway station in the after- 
 noon, found myself somewhat too early for the train. By way of 
 improving the time thus left on my hands, I betook myself to the 
 examination of a large pile of rubbish, consisting of shale and iron- 
 stone from one of the pits, and in which I had previously found 
 scales and teeth of fishes. In the blocks of hard carbonaceous 
 shale and earthy coal, of which the pile chiefly consisted, 
 scales, teeth and coprolites often appeared on the weathered ends 
 and surfaces as whitish spots. In looking for these, I observed one 
 of much greater size than usual, on the edge of a block, and on 
 splitting it open, found a large flattened skull, the cranial bones of 
 which remained entire on one side of the mass, while the palate 
 and teeth, in a more or less fragmentary state, came away with 
 the other half. Carefully trimming the larger specimen, and 
 gathering all the smaller fragments, 1 packed them up as safely 
 as possible, and returned from my little excursion much richer 
 than I had hoped. 
 
 The specimen, on further examination, proved somewhat puz- 
 zling. I supposed it to be, most probably, the head of a large 
 ganoid fish ; but it seemed different from any thing of this kind 
 with which I could compare it ; and at a distance from compara- 
 tive anatomists, and without sufficient means of determination, I 
 dared not refer it to anything higher in the animal scale. Hop- 
 ing for further light, I packed it up with some other specimens^ 
 and sent it to the Secretary of the Geological Society of London, 
 with an explanatory note as to its geological position, and request- 
 ing that it might be submitted to some competent osteologist for 
 examination. For a year or two however, it remained as quietly 
 
AIR-BREATHERS OP THE COAL PERIOD. 11 
 
 in the Society's collection as if in its original bed in the coal mine, 
 until attention having been attracted to such remains by the dis- 
 coveries made by Sir Charles Lyell and myself in 1852, at the South 
 Joggins, and published in 1853,* the Secretary or President of the. 
 Society re-discovered the specimen, and handed it to Prof. Owen, 
 by whom it was described in Dec., 1853,f under the name of 
 Baphctes planiccps, which may be interpreted the " flat-headed- 
 diving animal*' in allusion to the flatness of the creature's skull, 
 and the possibility that it may have been in the habit of diving. 
 
 The parts preserved in my specimen are the bones of the an- 
 terior and upper part of the skull in one fragment, and the teeth 
 and palatal bones in others. With respect to the former, Prof. 
 Owen recognizes in it the premaxillary (p.) (Fig. 1) and maxillary 
 bones, (m.) both presenting traces of the sockets of teeth, which 
 appear to be in a single series ; but other fragments show that in 
 part at least, they were in double series. The central portion of the 
 skull and part of the orbits are made up of the nasals, (n.) the 
 frontal (fr.) and the prefrontal (pf.) in a manner characteristic 
 of the Labyrinthodont reptiles, and not of fishes. The upper sur- 
 face of the bone, seen in some detached fragments, as in Fig. 4, has 
 a pitted surface, like that of the stone of a peach, as is the case 
 also in the Labyrinthodonts. In sections under the microscope, 
 the bone shows vascular canals and small rounded bone-cells, a 
 structure observed in Labyrinthodon, and in some of the larger 
 Saurians (Figs. 2 and 8). The teeth are conical, and somewhat 
 curved, the outer series from a line to two lines in diameter, and 
 the inner series three lines or more (Figs. 3 and 5). They are 
 implanted in shallow sockets in the maxillary and premaxillary 
 bones, and are anchylosed to the sockets. For the lower third, the 
 outer surface presents shallow vertical grooves, conformably with 
 the plicated character of the internal structure (Figs. 3, 7, and 10). 
 The upper portion is smooth, and its internal structure presents 
 
 * Journal of Geological Society of London, vol. ix. 
 
 f Journal of Geological Society, vol. x ; and additional notes, vol. xi. 
 
12 AIR-BtlEATHERS OP THE COAL PEKIOB. 
 
 merely radiating tubes of ivory, and concentric layers, (Figs. S 7 
 6, and 9). The whole of these characters are regarded as allying 
 the animal with the great crocodilian frogs of the Trias of Europe, 
 first known as Cheirotkerians, owing to the remarkable hand-like 
 impressions of their feet, and afterwards as Labyrinthodonts, from 
 the beautifully complicated convolutions of the ivory of their teeth. 
 
 The only additional remains attributable to this creature, found 
 since the publication of Professor Owen's description, are the 
 bone represented in Fig. 12, and the scute or scale represented 
 in I?ig. 11. The former may be a scapular or sternal bone, and, 
 if so, would warrant the belief that the creature possessed anterior 
 limbs of considerable size ; the proportion relatively to the skull 
 being much the same as in the American bullfrog. The latter is 
 marked in the same way as the bones of the head, and would 
 indicate that JSaphetes was protected by bony dermal scales, re- 
 sembling those of the crocodile. 
 
 There is one point illustrated by the bone represented in Fig. 
 12, to which I would earnestly invite the attention of comparative 
 anatomists. It is the distortion to which bones are subjected 
 when imbedded in soft deposits, especially those containing 
 vegetable matter. In modern peat bogs, skulls have been found 
 nearly as pliable as leather, owing to the partial removal of their 
 phosphate of lime ; and in clay beds they are often found softer 
 than chalk, from the removal of their animal matter. Human 
 skulls, buried under no great weight of earth, have often been 
 strangely distorted from this posthumous softening. Even teeth 
 . are affected in this way. In the remains of the old Indian 
 village of Hochelaga, #t Montreal, while the teeth of bears are 
 found in the drier and more sandy soil quite perfect and unal- 
 tered ; in damp places, and where they a.re imbedded in organic 
 matter thrown out from the cabins, they are softened, so that a 
 large canine may be easily compressed between the finger and 
 thumb. Changes of this kind have no doubt been experienced 
 by all the bones imbedded in coal, carbonaceous shale, and similar 
 deposits ; and in the great compression which the mass has ex- 
 
AIR-BREATHERS OP THE COAL PERIOD. 13 
 
 perienced, the bones, yielding with it, have been flattened and dis- 
 torted in the most remarkable manner. In the bones, in short, as 
 in the plants of the coal, the flattened specimen must not be ac- 
 cepted as representing the original form. - The bone represented 
 in Fig. 12, for example, must have been strong, and nearly cylin- 
 drical in its middle portion, and much curved ; but it has given 
 way to pressure, and has as it were been faulted along certain 
 lines, so as to lose almost entirely its original relief. The sec- 
 tional view in Fig. 13, represents some of these faults, with the 
 present profile of the bone, its original outline being represented 
 by the dotted line. The title of the present species to the speci- 
 fic name planiceps, is also in part dependent on this cause. No 
 doubt its head, like that of other batrachians, was somewhat flat, 
 but this has been much increased by pressure ; in so much that 
 the fragments of the specimen show that the palate is almost 
 brought into contact with the roof of the skull, and that scarcely a 
 quarter of an inch is left in some places for the depth of the great 
 orbits. The interior of the skull must have been filled with soft 
 slime, and this has been compressed into a hard stone. In like 
 manner, I shall have occasion to show, in reference to other rep- 
 tiles of the coal, that their bones have been much altered in form, 
 so that limb bones, which, when buried in a nearly erect position, 
 show broad and flat articulating surfaces, have these compressed 
 into mere edges, when the specimens lie horizontally, and that hol- 
 low bones have been fractured longitudinally, and pressed almost 
 perfectly flat. Anatomisls may be very easily misled by such ap- 
 pearances, and should carefully enquire as to tbe possibility 
 of their occurrence, before deducing inferences from the forms of 
 bones. 
 
 Of tbe general form and dimensions of Baphetes, the facts at 
 present known, do not enable us to say much. Its formidable 
 teeth and strong maxillary bones show that it must have devoured 
 animals of considerable size, probab ! y the fishes whose remains 
 are found with it, or the smaller reptiles of tbe coal. It must in 
 short have been crocodilian, rather than frog-like, in its mode of 
 
14 AIR-BREATHERS OF THE COAL PERIOD. 
 
 life ; but whether, like the labyrinthodonts, it had strong limbs and 
 a short body, or like the crocodiles, an elongated form and a power- 
 ful natatory tail, the remains do not decide. One of the limbs, or, 
 a vertebra of the tail would settle this question, but neither have 
 as yet been found. That there were large animals of the laby- 
 rinthodontal form in the coal period, is proved by the footprints 
 discovered by Dr. King in Pennsylvania, which may have been 
 produced by an animal of the type of Baphetes. On the other 
 hand that there were large swimming reptiles, seems established by 
 the recent discovery of the vertebrae of Eosaurus Acadianus, at 
 the Joggins, by Mr. Marsh.* The locomotion of fiaphetes must 
 have been vigorous and rapid, but it may have been 'effected both 
 on land and in water, and either by feet or tail, or both. 
 
 With the nature of its habitat we are better acquainted. The 
 area of the Albion Mines coal field was somewhat exceptional in 
 its character. It seems to have been a bay or indentation in the 
 Silurian land, separated from the remainder of the coal-field by a 
 high shfngle beach, now a bed of conglomerate. Owing to this 
 circumstance, while in the other portions of the Nova Scotia coal- 
 field, the beds of coal are thin, and alternate with sandstones and 
 shales, at the Albion Mines a vast thickness of almost unmixed 
 vegetable matter has been deposited, constituting the 'main seam' 
 of thirty-eight feet thick,and the 'deep seam' twenty -four feet thick, 
 as well as still thicker beds of highly carbonaceous shale. But, 
 though the area of the Albion coal measures was thus separated, 
 and preserved from marine incursions, it must have been often sub- 
 merged, and probably had connection with the sea, through rivers 
 or channels cutting the enclosing beach. Hence beds of earthy 
 matter occur in it, containing remains of large fishes. One of the 
 most important of these is that known as the " Holing stone," a 
 band of black highly carbonaceous shale, coaly matter, and clay 
 ironstone, occurring in the main seam, about five feet below its 
 roof, and varying in thickness from two inches to nearly two feet. 
 
 * Silliman's Journal, 1859. 
 
AIR-BREATHERS OF THE COAL PERIOD. 15 
 
 It was from this band, that the rubbish-heap, in which I found the 
 skull of Baphetes planiceps, was derived. It is a laminated bed, 
 sometimes hard and containing much ironstone, in other places 
 soft and shaly : but always black and carbonaceous, and often with 
 layers of coarse coal, though with few fossil plants retaining their 
 forms. It contains large round flat scales and flattened curved 
 teeth, which I attribute to a fish of the genus Rhizodus, resem- 
 bling, if not identical with, R. lancifer, Newberry. With these are 
 double pointed shark-like teeth, and long cylindrical spines of a 
 species of Diplodus, which I have named t). acinaces.\ There 
 are also shells of the minute Spirorbis, so common in the coal 
 measures of other parts of Nova Scotia, and abundance of frag- 
 ments of cpprolitic matter. I have also observed in it a few scales 
 having the peculiar one-sided form of those of Archegosaurus and 
 Dendrerpeton ; and which I may possibly describe and figure, 
 among miscellaneous indications of unknown creatures, in the end 
 of this memoir. 
 
 It is evident that the " Holing stone " indicates one of those 
 periods in which the Albion coal area, or a large part of it, was 
 under water, probably fresh or brackish, as there are no properly 
 marine shells in this, or any of the other beds of this coal series. 
 We may then imagine a large lake or lagune, loaded with trunks 
 of trees and decaying vegetable matter, having in its shallow parts, 
 and along its sides, dense brakes of Calamites, and forests of Sigil- 
 laria, Lepidodendron, and other trees of the period, extending far 
 on every side as damp pestilential swamps. In such a habitat, 
 uninviting to us, but no doubt suited to Baphetes, that creature 
 crawled through swamps and thickets, wallowed in flats of black 
 mud, or swam and dived in search of its finny prey. It was, in so 
 far as we know, the monarch of these swamps, though there is 
 evidence of the existence of similar creatures of this type quite as 
 large in other parts of the Nova Scotia coal field ; but my notice 
 of these I defer for the present, in hope that additional facts may 
 
 f Supplement to Acadian Geology, pp. 43 and 50. 
 
16 AIR-BREATHERS OP THE COAL PERIOD. 
 
 be discovered in respect to them. If this should not be the case, 
 they will be noticed among miscellaneous remains in the sequel. 
 
 EXPLANATION OF PLATE II. 
 Baphetes planiceps. 
 
 Fig. 1. Skull seen from below, half natural size. 
 
 " 2. Portion of bone of skull magnified, to show vascular canals and 
 bone-cells. 
 
 " 3. One of the largest teeth, natural size. 
 
 4. Sculpturing of skull, and margin of orbit, natural size. 
 
 5. Fragment of maxillary bone, with four teeth of the outer series* 
 and one of the inner large teeth, the points of the teeth re- 
 stored from fragments in other specimens. 
 
 " 6 and 7. Sections of a tooth magnified : 6, upper part ; f , lower 
 part, with convoluted dentine. 
 
 " 8. Section of bone in Fig. 2, more highly magnified. 
 
 " 9 and 10. Sections of tooth represented in Figs. 6 and 7, natural 
 size. 
 
 u 11. Dermal scale found with remains of Baphetes. 
 
 " 12. Scapular or sternal bone found with remains of Baphetes. 
 
 13. Longitudinal section of the middle of the same, showing the 
 manner in which it has been crushed. 
 
AIR-BREATHEKS OF THE COAL PERIOD. 17 
 
 IV. DENDRERPETON AOADIANUM. 
 Plate III. 
 
 The geology of Nova Scotia is largely indebted to Sir Charles 
 Lyell. Though much had previously been done by others, 
 his personal explorations in 1842, and his paper on the gypsife- 
 rous formation, published in the following year, first gave 
 form and shape to some of the more difficult features of the geo- 
 logy of the country, and brought it into relation with that of other 
 parts of the world. In geological investigation, as in many other 
 things, patient plodding may accumulate large stores of fact, but 
 the magic wand of genius is required to bring out the true value 
 and significance of these stores of knowledge. It is scarcely too 
 much to say that the explorations of a few weeks, and subsequent 
 study of the subject by Sir Charles, with the impulse and guidance 
 given to the labors of others, did as much for Nova Scotia, as 
 might have been effected by years of laborious work under 
 less competent heads. 
 
 Sir Charles naturally continued to take an interest in the geolo- 
 gy of Nova Scotia, and to entertain a desire to explore more fully 
 some of those magnificent coast sections which he had but hastily 
 examined ; and when, in 1851, he had occasion to revisit the United 
 States, he made an appointment with the writer of these pages to 
 spend a few days in renewed explorations of the cliffs of the South 
 Joggins. The object specially in view was the thorough examina- 
 tion of the beds of the true coal measures, with reference to their 
 contained fossils, and the conditions of accumulation of the coal ; and 
 the results were given to the world in a joint paper on " The re- 
 mains of a reptile and a land-shell discovered in the interior of an 
 erect tree in the coal measures of Nova Scotia," and in the writer's 
 paper on the " Coal Measures of the South Joggins ;"* while other 
 important investigations grew out of the following up of these 
 
 * Journal of the Geological Society of London ; Vols. ix and x j and 
 Acadian Geology. 
 
18 AIR-BREATHERS OP THE COAL PERIOD. 
 
 researches, and much matter in relation to the vegetable fossils still 
 remains to be worked up. It is with the more striking fact of 
 the discovery of the remains of a reptile in the coal measures that 
 we have now to do. 
 
 The South Joggins Section is, among other things, remarkable 
 for the number of beds which contain remains o erect trees 
 imbedded in situ: these trees are for the most part Sigillariae, 
 varying in diameter from six inches to five feet. They have grown 
 in underclays and wet soils, similar to those in which the coal was 
 accumulated; and these having been submerged or buried by 
 mud carried down by inundations, the trees, killed by the accu- 
 mulations around their stems, have decayed, and their tops being 
 broken off at the level of the mud or sand, the cylindrical cavi- 
 ties, left open by the disappearance of the wood, and preserved in 
 their form by the greater durability of the bark, have been filled 
 with sand and clay. This, now hardened into stone, constitutes 
 pillar-like casts of the trees, which may often be seen exposed in 
 the cliffs, and which, as these waste away, fall upon the beach. 
 The sandstones enveloping these pillared trunks of the ancient 
 Sigillarise of the coal, are laminated or bedded, and the laminae, 
 when exposed, split apart with the weather, so that the trees 
 themselves become split across; this being often aided by the 
 arrangement of the matter within the trunks, in layers more or 
 less corresponding to those without. Thus one of these fossil trees 
 usually falls to the beach in a series of discs, somewhat resembling 
 the grindstones which are extensively manufactured on the coast. 
 The surfaces of these fragments often exhibit remains of plants 
 which have been washed into the hollow trunks and have been 
 imbedded there ; and in our explorations of the shore, we always 
 carefully scrutinized such specimens, both with the view of observ- 
 ing whether they retained the superficial markings of Sigillariae, 
 and with reference to the fossils contained in them. It was while 
 examining a pile of these " fossil grindstones," that we were sur- 
 prised by finding on one of them what seemed to be fragments of 
 bone. On careful search other bones appeared, and they had the 
 
AIR-BREATHERS OF THE COAL PERIOD. 19 
 
 aspect, not of remains of fishes, of which many species are found 
 fossil in these coal measures, but rather of limb-bones of a quadru- 
 ped. The fallen pieces of the tree were carefully taken up, and 
 other bones disengaged, and at length a jaw with teeth made its 
 appearance. We felt quite confident, from the first, that these 
 bones were reptilian ; and the whole, being carefully packed and 
 labelled, were taken by Sir Charles to the United States, and sub- 
 mitted to Prof. J. Wyman of Cambridge ; who recognized their rep- 
 tilian character, and prepared descriptive notes of the principal 
 bones, which appeared to have belonged to two species. He also 
 obseryed among the fragments an object of different character, 
 apparently a shell ; which was recognized by Dr. Gould of Boston, 
 and subsequently by Mr. Deshayes, as probably a land-snail, and 
 has since been named Pupa vetusta. 
 
 The specimens were subsequently taken to London and re-exa- 
 mined by Prof. Owen, who confirmed Wyman's inferences, added 
 other characters to the description, and named the larger and 
 better preserved species Dendrerpeton Acadianum, in allusion to 
 its discovery in the interior of a tree, and to its native country of 
 Acadia or Nova Scotia. With the aid of Plate III, I shall now 
 endeavour to describe this species as fully as the materials at my 
 command will allow, and shall then make some remarks on its 
 affinities, habitat, and mode of life. It is necessary to state in 
 explanation of the fragmentary character of the remains repre- 
 sented in the plate, that in the decay of the animals imbedded in 
 the erect trees at the Joggins, their skeletons have become disar- 
 ticulated, and the portions scattered, either by falling into the in- 
 terstices of the vegetable fragments in the bottom of the hollow 
 trunks, or by the water with which these may have sometimes been 
 partly filled. We thus can obtain only separate bones ; and though all 
 of these are no doubt present in each case, it is impossible in break- 
 ing up the hard matrix to recover more than a small proportion of 
 them. For this reason I have been obliged tohave recourse, not merely 
 to the original specimen whose discovery is noticed above, but to 
 three others subsequently obtained by me ; all however belong- 
 
20 AIR-BREATHERS OF THE COAL PERIOD. 
 
 ing, on the evidence of the 'teeth and more important bones, to one 
 species, and all being nearly, though not absolutely, of the same 
 size. It is also proper to state that in the case of the original 
 specimen, and another still more perfect one, both of which are now 
 in London, I have been able to refer only to the published plates, and 
 *o add to these from parts of two additional individuals still in 
 my own collection. 
 
 In form, Dendrerpeton Acadianum was probably lizard- like ; 
 with a broad flat head, short stout limbs and an elongated tail ; 
 and having its skin, and more particularly that of the belly, pro- 
 tected by small bony plates closely overlapping each other. It 
 may have attained the length of two feet. The form of the head 
 is not unlike that of Baphetes, but longer in proportion ; and much 
 resembles that of the labyrinthodont reptiles of the Trias (Fig. 1). 
 The bones of the skull are sculptured as in Baphetes, but in a 
 smaller pattern (Figs. 8, 9). The nostrils are small, and near the 
 muzzle : the orbits are circular, and separated by a space of more 
 than their own diameter. In the upper jaw there is a series of con- 
 ical teeth on the maxillary and intermaxillary bones (Figs. 5, 15). 
 Those on the intermaxillaries are much larger than the others* 
 and have the aspect of tusks or canines (Figs. 3, 13). Within this 
 outer series of teeth, but implanted apparently in the same 
 bones, there is as in Archegosaurus a second series of teeth, 
 closely placed, or with intervals equal to the diameter of one 
 tooth. These inner teeth are longer than the others, implanted 
 in shallow sockets, to which they are anchylosed, and have the 
 dentine plicated, except toward the point (Figs. 2, 4, 6, T, 17). A 
 third group of teeth, blunt at the points, largely hollow in the in- 
 terior, and with the dentine quite simple, appears in detached bones, 
 which may represent the vomer (Fig. 12). Only a part of this 
 formidable armature of teeth appears in the skull represented in 
 Fig. 1, as the bones of the roof of the mouth have been removed, 
 adhering to the opposite side of the matrix ; but the fact of the 
 occurrence of two sets of teeth was ascertained by Prof Wyman, 
 from the original specimens, and is manifest in the fragment 
 
AIR-BREATHERS OF THE COAL PERIOD. 21 
 
 represented in Fig. 17 ; while the other teeth, supposed to be 
 vomerine, appear in fragments which must, from their size and 
 collocation, have belonged to Dendrerpeton. It will be observed 
 that all these teeth are anchylosed to the bone ; and that those of 
 the vomer are thinly walled and simple, the outer series on the 
 maxillaries and intermaxillaries simple and flattened, while the 
 inner series of teeth are conical and plicated. In the 
 lower jaw there was a uniform series of conical teeth, not per- 
 ceptibly enlarged toward the front ; at least this is the case in the 
 only specimen at present in my collection (Fig. 16) ; which is 
 however merely an imperfect cast in hard sandstone. 
 
 The scapular and sternal bones seem to have been well devel- 
 oped and strong, but only portions of them are known (Fig. 25.) 
 The fore limb of the adult animal, including the toes, must have 
 been four or five inches in length, and is of massive proportions. 
 The bones were hollow, and in the case of the phalanges the bony 
 walls were thin, so that they are often found crushed flat. The 
 humerus however was a strong bone, with thick walls and a can- 
 cellated structure toward its extremities ; still even these have 
 sometimes yielded to the great pressure to which they have been 
 subjected. Fig. 26 shows the humerus of the original specimen 
 of the species, and Fig. 10 exhibits a series of sections of a similar 
 bone, probably the humerus of a smaller individual. The cavity 
 of the interior of the limb-bones is usually filled with calc-spar 
 stained with organic matter, but showing no structure ; and the 
 inner side of the bony wall is smooth, without any indication of 
 cartilaginous matter lining it. 
 
 The vertebrae, in the external aspect of their bodies, remind one 
 of those of fishes, expanding toward the extremities, and being 
 deeply hollowed by conical cavities, which appear even to meet in 
 the centre. There is however a large and flattened neural spine. 
 The vertebrae are usually much crushed, and it is almost impos- 
 sible to disengage them from the stone. Fig. 21 exhibits the usual 
 form, and Fig. 22 another ; which, in its long neural and haemal 
 spines, reminds us of the caudal vertebrae of those batrachians and 
 
22 AIR-BREATHERS OF THE COAL PERIOD. 
 
 reptiles which have tails flattened for swimming, and probably in- 
 dicates that this was the case with Dendrerpeton. Fig. 23 is a 
 transverse section of a somewhat crushed vertebra, showing its os- 
 sified centrum and neural spine, and also the microscopic struc- 
 ture of the bone. The ribs are long and curved, with an expanded 
 head, near to which they are solid, but become hollow toward the 
 middle ; and the distal extremities are flattened and thin walled. 
 The posterior limb seems to have been not larger than the ante- 
 rior, perhaps smaller. The bones represented in Fig. 27, which I 
 refer to this member, probably belonged to a somewhat smaller 
 individual than that to which the humerus in Fig. 26 belonged. 
 The tibia is much flattened at the extremity, as in some labyrin- 
 thodonts, and the foot must have been broad, and probably suited for 
 swimming or walking on soft mud, or both. That the hind limb 
 was adapted for walking is shown, not merely by the form of the 
 bones, but also by that of the pelvis, the best preserved specimen 
 of which is represented in Fig. 28 ; but an iliac bone of still larger 
 size is figured in the Journal of the Geological Society, Vol. IX. 
 
 The external scales are thin, oblique-rhomboidal or elongated- 
 oval, marked with slight concentric lines, but otherwise smooth, 
 and having a thickened ridge or margin ; in which they resemble 
 those of ArcHegosaurus^ and also those ofPholidogasterpisciformis, 
 recently described by Huxley from the Edinburgh coal-field, an 
 animal which indeed appears in most respects to have a close affi- 
 nity with Dendrerpeton. The microscopic structure of the scales 
 is quite similar to that of the other bones, and different from that 
 of the scales of ganoid fishes, the shape of the cells being batra- 
 chian as in Fig. 11. Figs. 18 and 19 exhibit different forms of 
 the scales. 
 
 With respect to the affinities of the creature, I think it is ob- 
 vious that it presents some points of resemblance, on the one 
 hand to Archegosaurus, and on the other, to Labyrinthodon ; and 
 that it has the same singular mixture of ichthyic, batrachian, and 
 reptilian characters which distinguish these ancient animals, and 
 which give them the appearance of prototypes of the reptilian 
 
AIK-BREATHERS OF THE COAL PERIOD. 23 
 
 class. Professor Owen regards ArcJiegosaurus as the type of the 
 order Ganocephala, which he characterizes as having the head 
 protected by sculptured and polished ganoid plates, no occipital con- 
 dyles, teeth with converging folds of cement at their basal half, the 
 notochord persistent, the ribs short and straight, the limbs natato- 
 ry and small ; and holds that Dendrerpeton approaches more nearly 
 to this order than to the Labyrinthodonts. But at the time when 
 this opinion was expressed, he was not fully aware of the develop- 
 ment of the limbs and ribs, and of the ossified condition of the 
 vertebrae ; characters which, with the form of the skull, the ar- 
 rangement of the teeth, and the probable possession of occipital 
 condyles, appear to determine the scale in favour of the Labyrin- 
 thodonts. At the same time it must be admitted that Dendrerpe- 
 ton is far removed from the typical genus Lalyrinthodon, and 
 that in the characters in which it differs, it leans toward Arche- 
 gosaurus; closely resembling in thisits contemporary Pholidogaster 
 pisciformis already referred to. 
 
 This ancient inhabitant of the coal swamps of Nova Scotia, 
 was, in short, as we often find to be the case with the earliest 
 forms of life, the possessor of powers and structures not usually, 
 in the modern world, combined in a single species. It was cer- 
 tainly not a fish, yet its bony scales, and the form of its vertebrae, 
 and of its teeth, might, in the absence of other evidence, cause it to 
 be mistaken for one. We call it a batrachian, yet its dentition, the 
 sculpturing of the bones of its skull, which were certainly no more 
 external plates than the similar bones of a crocodile, its ribs, and 
 the structure of its limbs, remind us of the higher reptiles ; and 
 we do not know that it ever possessed gills, or passed through a 
 larval or fish-like condition. Still, in a great many important char- 
 acters, its structures are undoubtedly batrachian. It stands, in 
 short, in the same position with the Lepidodendra and SigiUarice 
 under whose shade it crept, which though placed by palseo-bota- 
 nists in alliance with certain modern groups of plants, manifestly 
 differed from these in many of their characters, and occupied a dif- 
 ferent position in nature. In the coal period, th -distinctions of 
 
24 AIR-BREATHERS OP THE COAL PERIOD. 
 
 physical and vital conditions were not well defined dry land 
 and water, terrestrial and aquatic plants and animals, and lower 
 and higher forms of animal and vegetable life, are consequently 
 not easily separated from each other. This is no doubt a state of 
 things characteristic of the earlier stages of the earth's history, 
 yet not necessarily so ; for there are some reasons, derived from fos- 
 sil plants, for believing that in the preceding Devonian period 
 there was less of this, and consequently that there may then have 
 been a higher and more varied animal life than in the coal period.* 
 Even in the modern world also, we still find local cases of this 
 early union of dissimilar conditions. It is in the swamps of 
 Africa, at one time dry, at another inundated, that such interme- 
 diate forms as Lepidosiren occur, to baffle the classificatory pow- 
 ers of naturalists ; and it is in the stagnant unaerated waters, half 
 swamp, half lake or river, and unfit for ordinary fishes, that the 
 semi-reptilian Amia and Lepidosteus still keep up the characters 
 of their palaeozoic predecessors. 
 
 The dentition of Dendrerpeton shows it to have been carnivo- 
 rous in a high degree. It may have captured fishes and smaller 
 reptiles, either on land or in water, and very probably fed on 
 dead carcases as well. If, as seems likely, the footprints referred 
 to in a previous section belong to Dendrerpeton, it must have fre- 
 quented the shores, either in search of garbage, or on its way to 
 and from the waters. The occurrence of its remains in the 
 stumps of Sigillaria, with land-snails and millipedes, shows also 
 that it crept in the shade of the woods in search of food ; and 
 under the head of coprolitic matter, in a subsequent section, I 
 shall show that remains of excrementitious substances, probably 
 of this species, contain fragments attributable to smaller reptiles, 
 and other animals of the land. 
 
 All the bones of Dendrerpeton hitherto found, as well as those 
 of the smaller reptilian species hereafter described, have been ob- 
 
 * See the author's paper on Devonian plants, Journal of the Geological 
 Society, Vol. xviii, p. 328. 
 
AIR-BREATHERS OF THE COAL PERIOD. 25 
 
 tained from the interior of erect Sigillariae, and all of these in one 
 of the many beds, which, at the Joggins, contain such remains. 
 The thick cellular inner bark of Sigillaria was very perishable ; 
 the slender woody axis was somewhat more durable ; but near 
 the surface of the stem, in large trunks, there was a layer of elon- 
 gated 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 in- 
 fluence of the weather, became a hollow shell of bark ; in the bot- 
 tom of which lay the decaying remains of the woody axis, and 
 shreds of the fibrous bark. In ordinary circumstances such hol- 
 low stems would be almost immediately filled with silt and sand, 
 deposited in the numerous inundations and subsidences of the 
 coal swamps. Where however they remained open for a consi- 
 derable time, they would constitute a series of pitfalls, into which 
 animals walking on the surface might be precipitated ; and being 
 probably often partly covered by remains of prostrate trunks, or 
 by vegetation growing around their mouths, they would be places 
 of retreat and abode for land-snails and such creatures. When 
 the surface was again inundated or submerged, all such animals, 
 with the remains of those which had fallen into the deeper pits, 
 would be imbedded in the sediment which would then fill up the 
 holes. These seem to have been the precise conditions of the 
 bed which has afforded all these remains, I may add that I be- 
 lieve all the trees, four or five in number, which have become 
 exposed in this bed since its discovery, have been ransacked for 
 such remains ; and that while all have afforded some reward for 
 the labour, some have been far more rich than others in their 
 contents. It is also to be observed that owing to the mode of 
 accumulation of the mass filling the trees, the bones are usually 
 found scattered in every position, and those of different species 
 intermingled; and that being often much more ^friable than the 
 
 * See a paper by the author, on the structures of coal ; Journal of 
 the Geological Society, Vol. xv ; also supplement to Acadian Geology. 
 
 D 
 
26 AIR-BREATHERS OF THE COAL PERIOD. 
 
 matrix, much labour is required for their development ; while 
 after all has been done, the result is a congeries of fragments like 
 tjiat presented by Plate III. The two specimens which displayed the 
 largest number of bones in juxtaposition, are one of Dendrerpeton 
 Acadianum, and one ofHylonomus Lyelli, both presented by me to 
 the geological Society oi London, and now in its collection ; but of 
 which I shall endeavour to obtain accurate representations for 
 this memoir. 
 
 In order more fully to illustrate the mode of occurence of these 
 remains, I quote the following notice of my last explorations in 
 the bed containing them, from the Journal of the Geological So- 
 ciety of London, for 1861 : 
 
 " In the bed which has hitherto alone afforded reptilian re- 
 mains in its erect trees, two additional examples of these were 
 exposed. One was on the beach, and in part removed by the sea. 
 The other was in the cliff, but so far disengaged that a miner 
 succeeded in bringing it down for me. In the first, comparatively 
 little was found. It afforded only a few shells of Pupa vetusta, 
 and scattered bones of a full-grown individual of Dendrerpeton 
 Acadianum. 
 
 " The second tree was more richly stored ; and, being in situ, 
 was very instructive as to the mode of occurence of the remains. 
 Like all the other trees in which reptilian bones have been found, 
 it sprang immediately from the surface of the six-inch coal in 
 Group XV. of my section* ; which is also Coal No. 15 of Sir W. 
 E. Logan's sectionf . Its diameter at the base was two feet, and its 
 height six feet, above which, however, an appearance of additional 
 height was given by the usual funnel-shaped sinking of the over- 
 lying beds toward the cavity of the trunk. The bark is well pre- 
 served in the state of bituminous coal, and presents externally a 
 longitudinally wrinkled surface, without ribs or leaf-scars ; but 
 within, on the * ligneous ' surface, or that of the inner bark, there 
 
 * Quart. Journ. Geol. Soc.'Vol. ix. p; 58, and Vol. x. p. 20. 
 t Reports of Geol. Surrey of Canada, 1845. 
 
AIR-BREATHERS OF THE COAL PERIOD. 27 
 
 are broad flat ribs, and transversely elongated scars. The ap- 
 pearances are precisely those which might be expected on an old 
 trunk of my Sigillaria Brownii ; to which species this tree may 
 have very well belonged.]; 
 
 " The contents of the trunk correspond with those of others pre- 
 viously found. At the bottom is the usual layer of mineral char- 
 coal, consisting of the fallen wood and bark of the tree itself. Above 
 this, about two feet of its height are filled with a confused mass of ve- 
 getable fragments, consisting of Cordaites, Lepidodendron, Uloden- 
 dron, Lepidostrobus, Calamites, Trigonocarpum, stipes and fronds 
 of ferns, and mineral charcoal ; the whole imbedded in a sandy 
 paste blackened by coaly matter. In, and at the top of this mass 
 occur the animal remains. The remainder of the trunk is oc- 
 cupied with grey and buff sandstone, containing a few fragments 
 of plants, but no remains of animals. 
 
 " Portions of six reptilian skeletons were obtained from this trunk. 
 The most important of these is a large and nearly complete skele- 
 ton of Dendrerpeton Acadianum* Another specimen found in 
 this trunk is a jaw of an animal about the size of Dendrerpeton 
 Acadianum, but with fewer and larger teeth.f The remaining 
 skeletons were imperfect^ and belonged to a small individual of 
 Dendrerpeton Acadianum, two of Hylonomus Lyelli, and one of 
 Hylonomus Wymani. The dislocated condition of these and 
 other skeletons is probably due to the circumstance that, when 
 they were introduced, the matter filling the trunk was a loose mass 
 of fragments, into the crevices of which the bones dropped, on 
 decay of the soft parts. Most of the skeletons lie at the sides of 
 the trunk, as if the animals had before death crept close to the 
 walls of their prison. At the time when the reptiles were intro- 
 duced, the hollow trunk must have been a pit four feet in depth. 
 
 J Quart. Journ. Geol. Soc. Vol. xrii. p. 523. 
 
 * Now in the collection of the Geological Society of London. Fig. 1, 
 represents the skull of this specimen, 
 f Since named and described by Prof. Owen as Hylerpeton Dawsoni 
 
28 AIR-BREATHERS OF THE COAL PERIOD. 
 
 A number of specimens of Pupa vetusta and Xylobius Sigillarite 
 were found, but nothing throwing further light on these species. 
 " The beds on a level with the top of this erect tree are arena- 
 ceous sandstones, with numerous erect Calamites. I searched the 
 surfaces of these beds in vain for bones or footprints of the rep- 
 tiles which must have traversed them, and which, but for the hol- 
 low erect trees, would apparently have left no trace of their exis- 
 tence. On a surface of similar character, sixty feet higher, and 
 separated by three coals, with their accompaniments, and a very 
 thick compact sandstone, I observed a series of footprints, which 
 may be those of Dendrerpeton or Hylonomus? 
 
 Through the kindness of the Council of the Geological Society 
 of London, the fine skeleton of Dendrerpeton Acadianum, sent by 
 me to the Society in 1861, has been returned for my inspection 
 in the preparation of this article. 
 
 I am now able to state, in addition to the facts already noticed 
 that the large furrowed teeth of the inner series were not 
 placed in the palatal bones, but on the maxillaries and intermax- 
 illaries, the outer series of smaller and simple teeth being borne 
 on the outer margin of these bones. The arrangement was thus 
 somewhat similar to that in Lepidosteus. Immediately within 
 the large teeth were the vomerine series, which were very numer- 
 ous and irregularly placed, but small, with the exception of a few 
 in front. They extended backward in two lines along both sides 
 of the palate, in this also resembling some ganoid fishes. 
 
 In this specimen, the lower jaw, remaining in place under the 
 skull, is seen to contain, especially toward the front, long fur- 
 rowed teeth like those of the upper jaw, implanted in round 'soc- 
 kets on the broad upper surface of the mandible, with others more 
 simple and of smaller size. 
 
 By carefully removing the stone,! have uncovered the occipital 
 condyles, which are double and square in outline, much like those 
 of Ldbyrinihodon, and not dissimilar from those of Sieboldia and 
 Menobranchus. 
 
AIR-BREATHERS OF THE COAL PERIOD. 29 
 
 Near the skull, the scales of the throat remain in their natural 
 position, and are seen to be densely imbricated, and arranged in 
 curved rows, diverging from the mesial line. The scales of the 
 abdomen are of larger size, and are scattered over the stone. 
 Those of the throat are of a narrow ovate form, those of the abdo- 
 men wider, and some of them tending to rhomboidal in outline. 
 
 Twenty-four vertebrae, in all, are seen in the specimen. Of these 
 thirteen occur in continuous series, and appear to be lumbar. 
 They are of small size, relatively to the dimensions of the head 
 and limbs, and indicate a weak and flexible back. Other verte- 
 bra, not in regular series, are dorsal, and have strong transverse 
 processes with oblique articulating surfaces. A few are perhaps 
 cervical and caudal. The bodies of the vertebra have continuous 
 bony walls, but thinner than in specimens of larger size. 
 
 One half of the pelvis is well preserved, and shows a broad 
 ilium, and strong ischiac and pubic bones. There are also broad 
 scapular, and probably sternal bones, but crushed and imperfect. 
 Few of the ribs remain, and these apparently only the smaller 
 ones, as compared with other skeletons of which I have portions. 
 
 Several of the bones of the limbs remain in sufficiently good 
 preservation to allow of measurement of their size. I am thus 
 enabled to give the following dimensions of parts of the animal. 
 
 Total length of skull, . 2-75 inches. 
 
 " breadth " at the orbits, 2 " 
 
 Length of humerus, 1*33 inch. 
 
 " " ulna, 1 " 
 
 " " femur, 1 
 
 " " rib, 0-T5 
 
 " " eleven vertebrae in series, 225 " 
 
 It would seem from these dimensions that the head was broad, 
 and the trunk slender; the anterior limb, including the foot, 
 half as long again as the head, and the posterior limb rather 
 smaller or shorter than the anterior. It would thus appear that 
 while the general form of the body was not unlike that of Meno- 
 branchus, the limbs were much larger, and must have carried the 
 
30 AIK-BREATHERS OP THE COAL PERIOD. 
 
 trunk without allowing any part of it to touch the ground, as 
 would -also seem to have been the case from the footprints found 
 in the coal-formation beds, and the size and form of the toes of 
 which make it likely that they belonged to this animal. 
 
 The limb-bones, though thin-walled atfd often crushed, evi- 
 dently had broad articulating surfaces ; and in the case of the fore- 
 limbs particularly, were large and strong in proportion to the di- 
 mensions of the head and vertebral column. 
 
 The large size of the fore-limb I suppose to have been related 
 lo a habit of walking or standing in shallow water, with the snout 
 in the air, in the manner of newts, and the more rapid movements 
 of the creature were probably performed by the tail. It is inter- 
 esting to observe that in Hylonomus the proportions of the limbs 
 were reversed the hind limbs being much larger than the fore 
 limbs. 
 
 From the relative dimensions of the bones, as compared with 
 those of other specimens in my possession, I presume that this in- 
 dividual was three-fourths grown, and I doubt if its total length 
 much exceeded one foot. 
 
 EXPLANATION OP PLATE III. 
 Dendrerpeton j&cadianum. 
 
 Fig. 1. Skull seen from below. 
 2. Inner tooth, magnified ; from the jaw, Fig. 17. 
 3. Tooth of intermaxillary, magnified ; from the bone in Fig. 13. 
 4. Series of inner teeth, less magnified. 
 6. Series of outer teeth of maxillary bone, Fig. 15, magnified. 
 11 6, 7. Sections of inner teeth. 
 
 M 8. Portion of bone of skull, outer surface, twice the natural size. 
 9. Super-temporal bone, twice the natural size. 
 M 10. Cross section of humerus ; (a) natural size ; (b) magnified ; (c) 
 
 portion more highly magnified, showing canals and bone 
 
 cells. 
 
 Perhaps increased by flattening. 
 
AIR-BREATHERS OP THE COAL PERIOD. 31 
 
 Fig. 11. Bone cells, highly magnified (after Quekett). 
 
 12. Vomer ? with teeth ; (a) tooth magnified. 
 
 " 13. Intermaxillary with teeth. 
 
 " 14. Section of tooth of intermaxillary ; (b) magnified ; (a) portion 
 highly magnified. 
 
 " 15. Maxillary bone with teeth. 
 
 " 16. Mandible with teeth. 
 
 17. Fragment of skull, with (a) outer teeth of maxillary ; (b) in- 
 ner teeth. 
 
 11 18. Cross section of a scale, magnified. 
 
 " 19. Outlines of scales, natural size. 
 
 " 20. Scale, twice natural size. 
 
 21. Vertebra. 
 
 " 22. Caudal vertebra, 
 
 " 23. Vertebra broken across, showing neural and central cavities ; 
 (a) natural size ; (b) section of a portion magnified, showing 
 canals and bone cells. 
 
 tt 24. Fragments of ribs. 
 
 " 25. Scapular bone. 
 
 " 26. Humerus, crushed at the proximal end, with fragment of the 
 radius. 
 
 " 27. Fragments of femur, tibia, and fibula. 
 
 11 28. Remains of pelvis. 
 
 29. Bones of the foot. 
 
 " 30. Group of bones of the foot, in situ. 
 All the above are of the natural size, unless otherwise stated. 
 
32 AIR-BREATHERS OF THE COAL PERIOD. 
 
 V. DENDRERPETON OWENI. 
 Plate IV. 
 
 Among the reptilian remains found in erect trees at the South 
 Joggins, there have occurred several portions of skeletons, which 
 from their sculptured cranial bones, plicated teeth, and the forms 
 of their scales and limb-bones, I have referred to the genus Den- 
 drerpeton, but to individuals of much smaller size than the full- 
 grown specimens of D. Acadianum. It did not occur to me to 
 suppose that these were specifically distinct from the larger indi- 
 viduals, until I observed that bones of this kind, contained in the 
 collections sent by me to the Geological Society, or represented 
 in the figures drawn to illustrate one of my papers, were referred 
 by Professor Owen, in his notes on these specimens and figures, 
 in the Journal of the Geological Society, to the genus Hylonomus ; 
 which is quite distinct from Dendrerpeton, as will be explained in 
 the sequel. 
 
 I was thus induced to re-examine all the specimens in my col- 
 lection, and the result has been to establish a strong probability 
 that there is in reality a second species of Dendrerpeton, smaller 
 than D. Acadianum^ and differing from it in several points. Thia 
 species I propose to name JD. Oweni. It differs from D. Acadia- 
 num in the following particulars : (1) Its much smaller size : 
 (2) Its long and hooked teeth ; PI. IV, Figs. 2 to 8 ; (it will be 
 seen that these teeth differ very markedly in their proportions 
 and form from those of the larger species represented in PL III) : 
 (8) The greater plication of the ivory in the intermaxillary teeth ; 
 Figs. 8, 9 ; (in D. Acadianum these teeth are, on the outside, 
 simple almost to the base, and plicated on the inner side, while 
 in this species they are plicated all around like the inner maxillary 
 teeth) : (4) The form of the skull, which has the orbits larger in 
 proportion, and is also shorter and broader. On the other hand, 
 when we have described the species of Hylonomus, it will be seen 
 that this animal, except in size, differs from them quite as widely 
 aa does D, Acadianwn. 
 
AIR-BREATHERS OF THE COAL PERIOD. 33 
 
 The distinctness of D. Oweni is further confirmed by the fact 
 that I possess small jaw bones of Dendrerpeton, about the size of 
 those of this species, but having the teeth similar in form to those 
 of the larger species ; these I suppose to have belonged to young 
 individuals. 
 
 On examining the figures, it will be seen that the bones of the 
 skull were corrugated as in the large Dendrerpeton, but with a 
 smaller pattern. The forms of the jaw-bones also, and of the ver- 
 tebrae, ribs, scapular bone, bones of the limbs, and bony scales, 
 are very similar, and indicate that in general form this creature 
 was not far removed from its larger relative. The bones of the 
 foot, represented in Fig. 14, especially deserve attention. This is 
 the most perfect foot of Dendrerpeton hitherto found ; and I have 
 enlarged it in the figure, in order more distinctly to show its parts. 
 It presents three long toes, with traces of a smaller one at each 
 side, so that there were probably five in all. If these toes be 
 compared with the footprints on the slab discovered by Dr. Hard- 
 ing, represented in PI. I, Fig. 2, it will be seen that they very 
 closely correspond, though the toes of the present species are 
 much smaller. The footprints are precisely those which we may 
 suppose an animal of the size of Dendrerpeton Acadianum would 
 have made, if, as the bones found render in every way probable, 
 this larger species had a foot similar to that of D. Oweni. I sup- 
 pose, for this reason, that these footprints are really those of Den- 
 drerpeton Acadianum} and that this species continued to exist 
 from the time of the lower coal measures, to the period when 
 those higher beds of the series, in which its bones are found at 
 the Joggins, were deposited. 
 
 The present species must have lived in the same places with 
 its larger relative j but may have differed somewhat in its habits. 
 Its longer and sharper teeth may have been better suited for de- 
 vouring worms, larvae or soft-skinned fishes, while those of the 
 larger Dendrerpeton were better adapted to deal with the mailed 
 ganoids of the period, or with those smaller reptiles which were 
 more or less protected with bony or horny scales. 
 
 
 
34 AIR-BREATHERS OF THE COAL PERIOD. 
 
 VI. REMAINS OF SKIN AND HORNY SCALES. 
 Plate I, Pig. 5; Plate IV, Figs. 22 to 34, and Plate V, Figs. 22 to 29. 
 
 In one of my earliest explorations of the reptile-bearing stumps 
 of the Joggins, I observed on some of the surfaces, patches of a 
 shining black substance, which on minute examination proved to 
 be the remains of cuticle, with horny scales and' other appendages. 
 The fragments were preserved ; but I found it impossible to deter- 
 mine with certainty to which of the species whose bones occur 
 with them they belonged, or even to ascertain the precise rela- 
 tions of the several fragments to each other. I therefore merely 
 mentioned them in general terms, and stated my belief that they 
 may have belonged to the species of Hylonomus.* More recently 
 other specimens have been obtained, and I have undertaken the 
 detailed examination of the whole. I shall now endeavour to 
 describe the principal or most continuous fragments, and after- 
 ward to consider the probabilities of their having belonged to cer- 
 tain of the reptiles entombed with them. I do this here, rather 
 than under the titles of these several animals, on account of the 
 uncertainty which still rests on the assignment of certain portions 
 of this cuticle to the species in question, and which renders it 
 more convenient to consider these peculiar remains in one place, 
 and to compare the different portions with each other. 
 
 (1) One of my specimens is a flattened portion of cuticle 2 J 
 inches in length. The greater jpart of the surface is smooth and 
 skining to the naked eye, and under the microscope shows only 
 a minute granulation. A limited portion of the upper, and I sup- 
 pose, anterior part is covered with imbricated scales, which must 
 have been membranous or horny, and generally have a small spot 
 or pore near the outer margin, some having in addition smaller 
 scales or points on their surfaces, (PI. IV, Figs. 22 and 25). In 
 contact with the upper part of this specimen there were many 
 fragments of the skull of Dendverpeton Oweni. 
 
 Journal of Geological Society, Vol. XYI. 
 
AIK-BREATHERS OF THE COAL PERIOD. 35 
 
 (2) Another portion of cuticle, similarly marked, appears to 
 preserve the form of the posterior part of the body and tail of the 
 animal, and also a mark representing the point of attachment of 
 the hind leg ; near to which, and along the dorsal ridge, is a por- 
 tion of the skin covered with much smaller scales. It is repre- 
 sented in PL T, fig. 5. This was found in close proximity to a 
 mass of bones of Dendrerpeton Oweni, mingled with some of Hy- 
 lonomus Lyelli. 
 
 (3) A third and still larger surface of integument with similar 
 markings, has upon it a number of vertebrae and detached bones 
 of the small reptile Hylonomus Wymani^ to be described in the 
 sequel ; for which species however it would be much too large a 
 covering. 
 
 (4) Another well preserved fragment, less than two inches in 
 length, exhibits very different markings. It is nearly covered 
 with very small imbricated scales, thicker than those on the spe- 
 cimens previously described. On either side of what seems to 
 have been the middle line of the back, there is a series of pointed 
 flat horny processes, which probably formed a double spinous crest. 
 Without these there are tufts of strong bristles, and exteriorly to 
 these last are rows of flat, thick, horny plates, transversely wrink- 
 led. Near to these was a row of conical truncated tubercles. 
 Sections of these appendages show them to have been horny and 
 attached to the cuticle. None of them have bony structure. 
 Figs. 23, 26, 27, 28, 29, 30, PI. IV, represent this portion of cu- 
 ticle, with magnified views of its markings, and of the structure of 
 one of the thicker scales. Fig. 26 shows a portion of the ordi- 
 nary scaly skin magnified and viewed by transmitted light. Fig. 
 27 exhibits a few of the bristle-like appendages from the point 
 marked a in fig. 23. Fig. 28 shows four of the bluntly-conical 
 points seen in a portion of skin a little beyond the margin of the 
 fragment in fig. 23, but evidently belonging to it. Fig. 24 is an 
 enlarged representation of one of the flat horny scales from the 
 point b in fig. 23 ; and fig. 29 is a magnified section of a por- 
 tion of the same scale, showing a compact translucent brown 
 
36 AIR-BREATHERS OF THE COAL PERIOD. 
 
 substance with round canals, and near the margin, a portion much 
 more abundantly supplied with these, apparently vascular canals, 
 while without this part there is a thin layer of more dense mate- 
 rial. Fig. 30 shows a portion of the surface of fig. 23, more 
 highly magnified, and displaying at a ordinary scales, at b 
 horny pointed organs, at c bristly appendages, and at d large 
 plates. The whole of these parts, though displaced by the flat- 
 tening and wrinkling of the skin, are in good preservation, and 
 show their characters in great perfection under the microscope. 
 They are all black and shining as if carved in jet. 
 
 (5) Near this last portion of cuticle, and possibly belonging to 
 it, are pointed and probably membranous appendages, marked on 
 each side with rows of scales not overlapping, and each with a 
 pore in its centre. The manner in which these appendages are 
 bent and wrinkled, shows that they must have been soft, except at 
 the tips, which seem to have been hard and horny, and they are 
 arranged in series, as if originally placed along the sides of the 
 neck or abdomen, or both. These appendages are represented 
 in PL IV, figs. 31 and 32. A magnified representation of the 
 point of one of them is given in fig. 33, and a small portion, stilJ 
 more highly magnified, in fig. 34. The use of these appendages 
 it is not easy to conjecture. They remind us of the gular pouches 
 of iguana, and of the lateral expansions of some geckos and of the 
 Draco volans* Possibly they formed lateral parachutes, aiding 
 the animal in moving over soft mud, or perhaps in leaping or 
 swimming. 
 
 (6) Some other fragments appear to have belonged to a diffe- 
 rent species from either of the foregoing, and are represented in 
 PI. V. The best preserved specimen (Fig. 22), which is about 
 one inch in length and half an inch in breadth, is covered with 
 very small imbricated scales. It is crossed by six or seven obscure 
 ridges, which both at the bottom and along a mesial line, pro- 
 jected into points covered with larger scales. A row of large 
 scales with round pores, connects these along the lower side (Figs. 
 23 and 24.) If, as seems probable, this fragment belonged to the 
 
AIE-BEEATHEES OP THE COAL PERIOD. 37 
 
 side of the trunk or tail, it would perhaps indicate a division of 
 the sub-cutaneous muscles into an upper and lower band, as in the 
 newts. A separate fragment, with transverse horny ridges (Figs. 
 26 and 27), and another with a longer lobe similar in structure to 
 those above mentioned (Figs. 28 and 29), may perhaps be re- 
 ferred to the same animal. A larger patch of skin presents simi- 
 lar imbricated scales, but without a mesial line, and with an edg- 
 ing of larger scales (Fig. 25). 
 
 Six species of reptiles have left their bones in the repositories 
 containing these remnants of cuticle. Of these, Dendrerpeton Aca- 
 dianum was an animal of too great sigfc to have been clothed 
 with integument of this character and of such dimensions. Hylo- 
 nomus aciedentatus, described in Section VIII, and Hylerpeton 
 Dawsoni, Section X, are each represented by only a single speci- 
 men, and these did not occur in proximity to any of the portions 
 of cuticle, except that the appendages in PI. IV, fig. 32, were 
 found near a specimen of the former. Of the three remaining 
 species, Dendrerpeton Oweni, from its size, the number of speci- 
 mens found, and the juxtaposition of their bones to the fragments 
 of cuticle, appears to have the best claim to the integument in- 
 cluded under Nos. 1, 2, and 3 ; and in this case, while the crea- 
 ture had its throat, and perhaps its abdomen, armed with bony 
 scales, its upper parts and tail, as well as its limbs, had a uniform 
 covering of small thin imbricated horny scales, in the manner of 
 many modern reptiles. 
 
 If the remaining portions of integument, Nos. 4 and 5, as would 
 seem likely, belonged to two species, both of smaller dimensions, 
 there would seem little reason to doubt that these were Hylono- 
 mus Lyelli (Section VII) and H, Wymani (Section IX). In 
 this case, both of these species must have possessed a highly or- 
 nate covering of horny scales and appendages, comparable with 
 that of any of the modern lizards, while there seems good reason 
 to believe, as stated in a previous paper, that they were in part 
 protected by bony scales somewhat like those of Dendrerpeton, 
 These points, however, we shall consider more in detail under 
 the sections which refer to the species of HylQnomus. 
 
38 AIR-BREATHERS OF THE COAL PERIOD. 
 
 Before leaving these curious specimens of ancient skin, the most 
 ancient I suppose known to exist, it is of interest to observe that 
 the thicker portions, when broken across, have the aspect of jet, 
 or of pure shining coal, and that thin slices, under the microscope, 
 have the same rich brown colour with that material, though rather 
 more translucent. When burned, fragments of the substance 
 give a strong flame, and a bituminous and ammoniacal odour. We 
 have thus an example of the production of coal from animal mem- 
 brane, no doubt gelatinous and horny in the first instance, but 
 which has proved itself capable of the same chemical changes 
 that have been experienced by the vegetable matter buried with 
 it. In order that this substance should be preserved in this way, 
 it would be necessary that it should either be kept dry and hard, 
 or that it should be immediately buried in matter Impervious to 
 air, and kept moist. The latter conditions are the more probable. 
 The preservative qualities of the peaty vegetable matter imbedded 
 with it must also be considered ; and it is possible that these hol- 
 low stumps partly filled with fragments of Sigillaria bark, may 
 have formed natural tan-pits, in which animal membranes would 
 be preserved in a manner impossible in ordinary sediments. If 
 this were the case, we may yet find an entire reptile, preserved 
 as a flattened mummy, in one of these strange repositories. 
 
 EXPLANATION OF PLATE IV. 
 Dendrerpeton Oweni, and Dermal Appendages. 
 
 Fig. 1. Skull. 
 
 " 2. Portion of mandible. 
 
 " 3. Maxillary bone, with outer teeth. 
 
 " 4. Teeth of same enlarged. 
 
 " 5. Maxillary bone, with inner teeth. 
 
 6. Tooth of same enlarged. ^ 
 
 " Y. Intermaxillary. 
 
 " 8. Tooth of same enlarged. 
 
 M 9. Section of same enlarged. 
 
AIR-BREATHERS OF THE COAL PERIOD. 39 
 
 Fig. 10 and 11. Vertebrae. 
 
 11 12. Portion of pelvis. 
 
 " 13. Fragments of ribs. 
 
 " 14. Bones of foot enlarged, (a) natural size. 
 
 " 15. Scapular bone. 
 
 " 16. Humerus. 
 
 " 17. Bones of hind leg. 
 
 " 18 and 19. Sculpturing of cranial bones, enlarged. 
 
 " 20. Bony scale. 
 
 " 21. Socket of inner tooth enlarged. 
 
 " 22 and 25. Integument of Dendrerpeton Oweni, with imbricated 
 
 scales. 
 
 " 23. Integument of Hylonomus Lyelli. 
 
 24, 26, 27, 28, 30. Scales and appendages of the same enlarged, 
 
 " 29. Section of scale represented in Fig. 24. 
 
 " 31. Angular pendants or processes of H. Lyelli. 
 
 " 32. The same of H. aciedentatus. 
 
 " 33 and 34. Portions of the same enlarged. 
 
40 AIR-BREATHERS OF THE COAL PERIOD. 
 
 VII. HTLONOMUS LTELLI. 
 \ 
 
 Plate V. 
 
 In the original reptiliferous tree,discovered by Sir C. Lyell and the 
 writer, at the Joggins, in 1851, there were, beside the bones of Den* 
 drerpeton Acadianum,some small elongated vertebrae, evidently of a 
 different species. , These were first detected by Prof. Wyman, in 
 his examination of these specimens, and were figured, but not named, 
 in the notice of the specimens in the Journal of the Geological 
 Society, Vol. IX. In a subsequent visit to the Joggins, I obtained 
 from another erect stump many additional remains of these smaller 
 reptiles, and, on careful comparison of the specimens, was induced 
 to refer them to three species, all apparently generically allied . 
 I proposed for them the generic name Hylonomus, " forest-dweller." 
 They were described in the proceedings of the Geological Society 
 for 1859, with illustrations of the teeth and other characteristic 
 parts.* The smaller species first described I named H. Wymani ; 
 the next in size, that to which this article refers, and which was 
 represented by a larger number of specimens, I adopted as the 
 type of the genus, and dedicated to Sir Charles Lyell. The 
 third and largest, represented only by a few fragments of a single 
 skeleton, was named H. aciedentatus. 
 
 Hylonomus Lyelli was an animal of small size. Its skull is about 
 an inch in length, and its whole body, even if, as was likely, fur- 
 nished with a tail, could not have been more than six or seven 
 inches long. No complete example of its skull has been found. 
 The bones appear to have been thin and easily separable j and 
 even when they remain together, are so much crushed as to render 
 the shape of the skull not easily discernible. They are smooth on 
 the outer surface to the naked eye ; and under a lens show only 
 delicate uneven striae and minute dots. They are more dense and 
 hard than those of Dendrerpeton, and the bone-cells are more 
 elongated in form. The bones of the snout would seem to have been 
 
 Journal of Geological Society, Vol. XYI. 
 
AIR-BREATHERS OP THE COAL PERIOD. 41 
 
 somewhat elongated and narrow. A specimen in my possession 
 shows the parietal and occipital bones, or the greater part 
 of them, united and retaining their form. We learn from them 
 that the brain-case was rounded, and that there was a parietal 
 foramen. There would seem also to have been two occipital 
 condyles ; (see plate V, fig. 8.). Several well preserved specimens 
 of the maxillary and mandibular bones have been obtained. They 
 are smooth, or nearly so, like those of the skull, and are furnished 
 with numerous sharp, conical, teeth, anchylosed to the jaw, in a 
 partial groove formed by the outer ridge of the bone. In the an- 
 terior part of the lower jaw there is a- group of teeth larger than 
 the others. The intermaxillary bone has not been observed. 
 (Figs. 1, 2, 3, 4, 5, 6.) The total number of teeth in each ramus 
 of the lower jaw was about forty, and the number in each max- 
 illary bone about thirty. The teeth are perfectly simple, hollow 
 within, and with very fine radiating tubes of ivory. (Fig. 7, a and 
 b.) The vertebra? have the bodies cylindrical or hour-glass 
 shaped, covered with a thin, hard, bony plate, and having within 
 a cavity of the form of two cones, attached by the apices. This 
 cavity was completely surrounded by bone, as it is filled with 
 stained calc-spar in the same manner as the cavities of the limb 
 bones. It' was probably occupied by cartilage. The vertebrae were 
 apparently bi-concave. The neural spines are short and broad, with 
 zygapophyses, and are not separable from the bodies, the 
 neural arches being perfectly anchylosed to the bodies of the ver- 
 tebrae. There are, on the dorsal vertebrae, strong diapophyses or lateral 
 spines, to which the ribs were articulated. (Figs. 15, 16, 17.) The 
 ribs are long, curved, and at the proximal end have a shoulder and 
 neck. (Figs. 1, 10, 18.) They are hollow, with thin hard 
 bony walls. The anterior limb, judging from the fragments pro- 
 cured, seems to have been slender, with long toes, four or possibly 
 five in number. A humerus is seen in fig. 1, and bones of the 
 toes magnified in fig. 11. The posterior limb was longer and 
 stronger, and attached to a pelvis so large and broad as to give the 
 impression that the creature enlarged considerably in size toward 
 
 P 
 
42 AIR-BREATHERS OF THE COAL PERIOD. 
 
 the posterior extremity of the body, and that it may have been in the 
 habit of sitting erect. The thigh bone is well formed, with a dis- 
 tinct head and trochanter, and the lower extremity flattened and 
 moulded into two articulating surfaces for the tibia and fibula, the 
 fragments of which show that they were much shorter. The toes 
 of the hind feet have been seen only in detached joints. They 
 seem to have been thicker than those of the fore foot. Detached 
 vertebrae, which seem to be caudal, have been found, but the 
 length of the tail is unknown. The limb bones are usually some- 
 what crushed and flattened, especially at their articular extremities, 
 and this seems to have led to the error of supposing that this 
 flattened form was their normal condition ; there can be no doubt, 
 however, that it is merely an effect of pressure. The limb bones 
 present in cross section a wall of dense bone with elongated bone- 
 cells, surrounding a cavity now filled with brown calc-spar, and 
 originally occupied with cartilage or marrow. (Figs. 12, 13, 14.) 
 Nothing is more remarkable in the skeleton of this creature than 
 the contrast between the perfect and beautiful forms of its bones, 
 and their imperfectly ossified condition, a circumstance which 
 raises the question whether these specimens may not represent the 
 young of some reptile of larger size. 
 
 The dermal covering of this animal is represented in part by oval 
 bony scales, which are so constantly associated with its bones that 
 I can have no doubt that they belonged to it, being, perhaps, the 
 clothing of its lower or abdominal parts ; while above,it was probably 
 clad in the beautiful scaly covering described in the last sec- 
 tion. The bony scales are represented magnified in Plate V. figs. 
 19. 20, and 21. It will be seen that they differ in form from those 
 of Dendrerpeton ; they are also much thicker. On the inner side 
 they are concave, with a curved ledge or thickened border at one 
 edge. On the outer side they present concentric lines of growth. 
 
 The only specimens which afford much information as to the 
 general form of Hylonomus Lyelli are those represented in Plate 
 V, figs. 1 and 9. The first is the original specimen, from which 
 I described the species in the paper already referred to. The 
 
AIR-BREATHERS OF THE COAL PERIOD. 43 
 
 bones, being small and of dark colour, are not very conspicuous, 
 and many of them are broken, but many are beautifully perfect ; 
 and even those which are removed have left very distinct moulds 
 of their form in the fine-grained matrix. In the figure I have 
 carefully traced their outlines in their natural position, with the ex- 
 ception of the maxillary bone and mandible, which are removed 
 from their place in the matrix, to bring the whole into a more com- 
 pact form. The specimen also shows, in addition to the bones 
 delineated, many fragments of the skull and scapular bones, crushed 
 in such a manner that their forms cannot be distinguished. The 
 specimen shows remains of thirty vertebrae, of which four appear 
 to belong to the neck, and the rest are probably nearly all dorsal 
 and lumbar. Three of the most perfect are represented enlarged, 
 in figs. 15 and 16. Of about twenty ribs, more or less complete 
 fragments remain. The fore limb is represented only by the im- 
 pression of a humerus, (e), but other bones which may have 
 belonged to it are scattered elsewhere on the stone. The pelvis, (i) 
 is nearly entire, though crushed and flattened. One thigh bone 
 remains tolerably perfect, and beside it lie the tibia and a part of 
 the fibula, with seyeral bones of the foot The dimensions of these 
 parts are as follows : 
 
 Length of maxillary O.T inch. 
 
 " mandible 0.7 " 
 
 " longest rib, (chord) 0.6 
 
 " humerus 0.5 " 
 
 Length of femur , 0.7 inch. 
 
 tibia 0.45" 
 
 " principal bone of pelvis 0.7 " 
 
 The other specimen above referred to, (Fig. 9.) shows the bones 
 of the trunk, and part of those of the hind and fore limb of a small 
 individual, nearly in their natural position. This specimen I have 
 very recently obtained, in breaking open a mass of matrix in which 
 I did not suspect its existence. It shows the humerus and radius 
 and ulna in a tolerable state of preservation, with a fragment of 
 the scapula. About thirteen dorsal and lumbar vertebrae can be 
 
44 AIR-BREATHERS OF THE COAL PERIOD. 
 
 made out, nearly in their natural position ; and there are remains 
 of five of the ribs. The hind limb is represented by fragments of 
 the femur, tibia, and fibula. I believe that the maxillary repre- 
 sented in fig. 3, though now in a detached piece of stone, belonged 
 to this skeleton. 
 
 While referring to these, my most perfect specimens, I think it 
 proper to quote my original description of the species, based on 
 the first of them, and published in 1859 ; as the subject has since 
 been unfortunately obscured by inaccurate descriptions, consequent 
 on the mixture of specimens and drawings, sent by me to London 
 for further examination. I quote from the journal of the Geolo- 
 gical Society, Vol. XVI. 
 
 " HYLONOMUS, gen. nov." 
 
 " The other reptilian remains represent three species belonging 
 to a generic form, which, so far as I am aware, has not been pre- 
 viously observed, and for which, in allusion to its forest habitat, I 
 propose the above name. As its typical species I. shall describe 
 that which I would name Hylonomus Lyelli. Its cranial bones 
 are thin and smooth ; the condyle I have not been able to observe, 
 but there is a parietal foramen, and the parietal bones are arched 
 in such a manner as to indicate a rounded rather than flattened 
 skull, and a somewhat capacious brain-case. Its teeth are nume- 
 rous (about twenty-six in each maxillary bone), elongated, conical, 
 closely set in a single series, in a furrow, protected externally by 
 an elevated alveolar ridge. In the intermaxillaries and extremities 
 of the mandibles the teeth are larger than elsewhere. Fig. 14, 
 (Fig. 5, Plate V. of this paper) represents a portion of the teeth of 
 the maxillary bone as exposed by the fracture of the outer ridge. 
 The vertebrae are imperfectly preserved, but appear to have been 
 ossified, bi-concave, and with well-developed spinous processes. The 
 ribs are long and curved ; and there are traces of numerous acces- 
 sory pieces which have been attached to their extremities. The 
 pelvis is of large size and remarkable form ; the ilium long and 
 expanded below ; the ischium greatly expanded ; the pubis ex- 
 
AIR-BREATHERS OF THE COAL PERIOD. 45 
 
 paneled and triangular where it joins the ischium, and round and 
 arched toward the symphysis. The femur is thick and nearly 
 straight, the tibia short and stout, the fibula slender, the phalan- 
 ges broad. The hind limb thus largely developed must have been 
 capable of supporting the whole weight of the body in standing or 
 leaping. The anterior extremities appear to have been compara- 
 tively slender, with thin and long fingers. A few scattered verte- 
 bra? lying posteriorly to the pelvis, may perhaps be remains of a 
 tail. There was a dermal covering of small ovate bony scales, of 
 which, however, only a" few scattered specimens remain. This 
 species is evidently quite remote from the ganocephalous and laby- 
 rinthodont types of batrachians, and in many respects approaches 
 to lacertians. It may perhaps be allied to the Telerpeton of Elgin, 
 but does not appear to resemble any reptile hitherto found in the 
 coal-formation." 
 
 It is evident, from the remains thus described, that we have in 
 Hylonomus Lyelli an animal of lacertian form, with large and 
 stout hind limbs, and somewhat smaller fore limbs, capable of walk- 
 ing and running on land ; and though its vertebrae were imperfectly 
 ossified externally, yet the outer walls were sufficiently strong, and 
 their articulation sufficiently firm, to have enabled the creature to 
 erect itself on its hind limbs, or to leap. They were certainly pro- 
 portionally larger and much more firmly knit than those of Den- 
 drerpeton. Further, the ribs were long and much curved, and im- 
 ply a respiration of a higher character than that of modern 
 batrachians, and consequently a more highly vitalized muscular 
 system. If to these structural points we add the somewhat rounded 
 skull, indicating a large brain, we have before us a creature which, 
 however puzzling in its affinities when anatomically considered, is 
 clearly not to be ranked as low in the scale of creation as modern 
 tailed batrachians, or even as the frogs and toads. We must add 
 to these also, as important points of difference, the bony scales 
 with which it was armed below, and the ornate apparatus of horny 
 appendages, with which it was clad above. These last, as described 
 in the last section, and illustrated in Plate IV., shew that this little 
 
46 AIR-BREATHERS OF THE COAL PERIOD. 
 
 animal was not a squalid, slimy dweller in mud, like Menobranchus 
 and its allies, but rather a beautiful and sprightly tenant of the 
 coal-formation thickets, vying in brilliancy, and perhaps in colour- 
 ng, with the insects which it pursued and devoured. Remains of 
 as many as eight or ten individuals have been obtained from three 
 erect sigillariae, indicating that these creatures were quite abun- 
 dant, as well as active and terrestrial in their mode of life. 
 
 With respect to the affinities of this species, I think it is abun- 
 dantly manifest that it presents no close relationship with any rep. 
 tile hitherto discovered in the Carboniferous system. The only in- 
 dications of which I am aware of animals of this age, likely to be 
 of similar type, are certain vertebrae discovered by Mr. Wheatley 
 and Dr Newberry, in the coal formation of Ohio, and described, 
 but not named, by Prof. Wyman, in Silliman's Journal, Vol. XXV, 
 in connection with the singular bratrachian named by him Rani- 
 ceps Lyelli ; which, in its broad frog-like head and want of 
 ribs, differs materially from the creature now under examination. 
 It is scarcely necessary to say that the characters above described, 
 and illustrated by the figures in Plate V, entirely remove this ani- 
 mal from Archegosaurus and Labyrinthodon, as well as from all 
 the other creatures associated with them in the orders G-ano- 
 cephala and Labyrinthodontia of Owen. Equal difficulties attend., 
 the attempt to place it in any other group of recent or ex- 
 tinct batrachians or proper reptiles. The structures of the skull, and 
 of some points in the vertebrae, certainly resemble those of batra- 
 chians ; but on the other hand, the well-developed ribs, evidently 
 adapted to enlarge the chest in respiration, the broad pelvis, and 
 the cutaneous covering, are unexampled in modern batrachians, 
 and assimilate the creature to the true lizards. I have already, in 
 my original description above quoted, expressed my belief that 
 Hylonomus may have had lacertian affinities, but I do not desire 
 to speak positively in this matter ; and shall content myself with 
 stating the following alternatives as to the probable relations of 
 these animals. (l)They may have been true reptiles of low type, 
 and with batrachian tendencies. (2) They may have been repre- 
 
AIR-BREATHERS OF THE COAL PERIOD. 47 
 
 sentatives of a new family of batrachians, exhibiting in some points 
 lacertian affinities. (3) They may have been the young of 
 some larger reptile, too large and vigorous to be entrapped in the 
 pit-falls presented by the hollow Sigillaria stumps, and in its 
 adult state losing the batrachian peculiarities apparent in the young. 
 Whichever of these views we may adopt, the fact remains, that in 
 the structure of this curious little creature we have peculiarities 
 both batrachian and lacertian, in so far as our experience of modern 
 animals is concerned. It would however accord with observed 
 facts in relation to other groups of extinct animals, that the primi- 
 tive batrachians of the coal period should embrace in their struc- 
 tures, points in after times restricted to the true reptiles. On the 
 other hand, it would equally accord with such facts that the first- 
 born of lacertians should lean toward a lower type, by which they 
 may have been preceded. My present impression is, that they 
 may constitute a separate family or order, to which I would give 
 the name of MICROSAURIA, and which may be regarded as allied, on 
 the one hand, to certain of the humbler lizards, as the Gecko or 
 Agama, and, on the other, to the tailed batrachians. 
 
 It is likely that Hylonomus Lyelli was less aquatic in its habits 
 than Dendrerpeton. Its food consisted, apparently, of insects and 
 similar creatures. The teeth would indicate this, and near its bones 
 there are portions of coprolite, containing remains of insects and 
 rnyriapods. It probably occasionally fell a prey to Dendrerpeton, 
 as bones, which may have belonged either to young individuals of 
 this species or to its smaller congener H. Wymani, are found in lar- 
 ger coprolites, which may be referred with probability to Dendrer- 
 Acadianum. 
 
48 AIR-BREATHERS OP THE COAL PERIOD. 
 
 EXPLANATION OF PLATE V. 
 Hylonomus Lyelli, and Dermal appendages. 
 
 Fig. 1 .Remains of a skeleton of a large individual of Hylonomus Lyelli ; 
 
 (a) Maxillary; (6) Mandible; (c) Ribs; (d) Vertebrae 5 
 
 (e) Humerus; (/) Femur; (g) Tibia; (A) Fibula, (0 
 
 Pelvis ; (fc) Foot. 
 " 2. Right Mandible. *n\ 
 3. Maxillary. \^ 
 
 4j 5. Portions of Maxillary, magnified. 
 6. Extremity of Mandible, magnified. 
 7. Sections of teeth ; (a) magnified, (6) highly magnified. 
 " 8. Portion of cranium, magnified ; (a) natural size, (6) transverse 
 
 section. 
 " 9. Skeleton of the trunk of a small individual of H. Lyelli; (a) 
 
 Fore limb, (6) Hind limb, (c) Ribs. 
 " 10. Ribs from the slab, Fig. 1, magnified. 
 " 11. Fore foot, magnified ; (a) natural size. 
 " 12. Cross section of flattened femur, magnified. 
 " 13, 14. Portions of the bone of the same, more highly magnified. 
 " 15. Pair of Vertebrae (dorsal), magnified. 
 16. Vertebra magnified. 
 1 7. Vertebra broken across and magnified, showing (a) neural arch, 
 
 (6) diapophysis, and (c) central cavity. 
 " 18. Head of a rib, magnified. 
 " 19, 20,21. Bony scales, magnified, (a) natural size. 
 " 22. Portion of cuticle, probably of Hylonomus Wymani. 
 " 23, 24. Parts of the same magnified. 
 " 25. Lower margin of another portion of cuticle, magnified. 
 " 26, 27. Ridged horny scale, natural size and magnified. 
 " 28, 29. Cutaneous lobe, natural size and magnified. 
 
AIR-BREATHERS OF THE COAL PERIOD. 49 
 
 VIII. HYLONOMUS ACIEDENTATUS. 
 Plate VI, Figs. 1 to 16. 
 
 This species is founded on a single imperfect specimen obtained 
 by me at the Joggins in 1859, and described in the Journal of 
 the Geological Society, Vol. XVI. In this description, I men- 
 tioned, as probably belonging to this species, certain detached 
 bones which I have since found reason to attribute to Den- 
 drerpeton Oweni. These did not however materially interfere 
 with the characters of species, which I shall give here from 
 the fragments represented in Plate VI, Figs. 1 to 16, and which 
 occur together in the matrix in such a manner as to render it 
 certain that they belonged to the same individual. 
 
 In size, H. aciedent&tus was about twice as large as the species 
 last described. Its teeth are very different in form. Those on 
 the maxillary and lower jaw are stout and short, placed in a 
 close and even series on the inner side of a ridge or plate of bone. 
 Viewed from the side they are of a spatulate form, and pre- 
 sent a somewhat broad edge at top as in Fig. 4. Viewed in 
 the opposite direction, they are seen to be very thick in a direc- 
 tion transverse to that of the jaw, and are wedge-shaped as in 
 Fig. 5. There are about forty on each side of the mandible, and 
 about thirty on each maxillary, as seen in Figs. 1, 2, and 3, of 
 which the two first are magnified slightly, the last natural size.* 
 
 Since the publication of my previous paper, I have ascertained 
 that the intermaxillary bones bore teeth of the form represented 
 in Fig. 6. They are larger than the others, thick and coming to 
 a blunt point, which is seamed with longitudinal and slightly 
 spiral ridges* This singular tooth must have been a most effi- 
 cient instrument for crushing and penetrating the coats of crusta- 
 ceans and insects, or the bony armour of the smaller ganoid fishes. 
 Remains exist at the extremity of the lower jaw, which show that 
 
 * In Prof. Owen's paper, J.G.S., Vol. 18, this bone is figured, but in- 
 correctly stated to be twice natural size, and referred to H. Lyelli. 
 
 a 
 
50 AIR-BREATHERS OF THE COAL PERIOD. 
 
 a few teeth there also were larger than the others, but whether 
 they differed in form cannot be determined. The pulp cavity of 
 the teeth is less extensive in proportion than in H. Lyelli, and the 
 structure in the cross section is simple, showing merely radiating 
 ivory tubes, as in Fig. 7. The bone represented in Fig. 8, was 
 found with these remains, and as it is too large for the last spe- 
 cies, and different from anything known in Dendrerpeton, it pro- 
 bably belongs to the creature now under consideration. It is thin 
 and smooth, except at the upper margin, where it has in the 
 centre a group of small conical teeth. It evidently belongs to 
 the palate, and somewhat resembles the palatal bone of Meno- 
 Iranchus, but is broader, and the latter has no teeth. Detached 
 fragments of the skull show that its bones were thin and dense 
 and smooth on the surface as in H. Lyelli. That represented in 
 Fig. 9 would seem to be a frontal bone seen from the inside. 
 
 The remains of H. aciedentatus are too scanty to warrant much 
 certain inference as to its form. Its vertebrae would seem to 
 have resembled those of H. Lyelli, but to have been elongated 
 and more thoroughly ossified (Fig. 16). Its ribs are similar in 
 form and proportion to those of the last named species (Figs. 10 
 and 11). A pelvic bone and some detached phalangial bones 
 (Figs. 12 and 13) as well as very fragmentary limb bones, would 
 indicate that its limbs were well developed. Its external scales 
 are similar to those of the last species but larger, and a few frag- 
 ments of skin show scales and appendages similar to those of H. 
 Lyelli, but of greater dimensions (Figs. 15 and 62). The micros- 
 copic structure of its bone is also similar to that in the last species 
 (Fig. 17). No doubt a more perfect specimen would show many 
 points of difference between these species, not now appreciable ; 
 but in the mean time the very different form of the teeth is a 
 sufficient distinction. In H. Lyelli these are conical and pointed. 
 In the present species they are of a peculiar wedge shape their 
 diameter transversely to the jaw being the greatest at the base, 
 while at the top they are sharpened to an edge. The peculiar 
 form of the intermaxillary teeth may also serve as a distinctive 
 
AIE-BEEATHEES OF THE COAL PEBIOD. 51 
 
 character, though those of H. Lyelli are not yet known. The 
 form of the vertebrae would further seem to indicate different pro- 
 portions of body. On the whole, while this species is in all pro- 
 bability generically related to the last, it is certainly specifically 
 distinct. Its habits and food may have been similar, but its den- 
 tal apparatus was stronger and more formidable. 
 
 EXPLANATION OF PLATE VI, FIGS. 1 TO 16, AND FIG. 62. 
 Hylonomus aciedentatus. 
 
 Fig. } 1 Maxillary bone, magnified, (a) natural size. 
 
 " 2 Mandible magnified, (a) natural size. 
 
 " 3 Portion of mandible, natural size. 
 
 " 4 and 5 Tooth, seen from the side and front. 
 
 6 Tooth of intermaxillary. 
 
 " T Cross section of tooth, magnified. 
 
 " 8 Palatal bone with teeth. 
 
 9 Frontal bone. 
 
 " 10 and 11 Rib natural size and cross section enlarged. 
 
 " 12 Pelvic bone. 
 
 " 13 Phalangial bone. 
 
 " 14 and 15 Bony scales magnified. 
 
 " 16 Broken vertebra. 
 
 " 62 Portion of skin with horny scales. 
 
52 AIR-BKEATHERS OF THE COAL PERIOD, 
 
 IX. HYLONOMUS WYMANI. 
 Plate VI, Figs. 18 to 31. 
 
 This is the species of ffylonomus originally detected by Pro!. 
 Wyman in the specimens brought from the Joggins by Sir Cr 
 Lyell and myself. Remains of several additional individuals have 
 since been found, but no skeleton approaching to completeness. I 
 shall describe this the most diminutive of the reptiles of the Nova 
 Scotia coal, with the aid of the fragments represented in Plate 
 VI, Figs. 18 to 31, most of which are almost microscopic in size. 
 
 The skull seems to have been much of the same form as in Hy- 
 lonomus Lyelli, but very thin and delicate, so that all the speci- 
 mens hitherto found are crushed and fragmentary. The maxil- 
 lary and mandibular bones are furnished with teeth which are 
 bluntly conical in form, and in the latter bone seem to be confined 
 to its front part, or to be very small posteriorly. They are thus 
 much fewer in number than in th species last named. I have 
 been able to make out only 22 in the lower jaw, and they are 
 alternately large and small, as if replaced in this manner as worn 
 out. Their structure is of the same simple character as in the 
 other species of ffyknomm, and they have large pulp cavities. 
 
 The vertebrae of this species are singular and characteristic. 
 The bodies are elongated and hour-glass shaped, with an internal 
 cavity of the same form rilled with calc spar (Fig. 30), and pro- 
 bably once occupied by cartilage. They have, in the dorsal re- 
 gion at least, strong articulating and lateral processes, and were 
 furnished with numerous delicate ribs (Figs. 24, 25, 27); In one 
 of my specimens as many as 38 of these little vertebrae may be 
 seen lying together, and many of them attached to each other. 
 This would indicate that the body was long and slender. It was 
 furnished with limbs, similar to those of H. Lyelli, but very small 
 and slender. The pelvis is of the same expanded form with that 
 of the last species, and a pair of fore feet lying together on one 
 slab, show the remain* of four slender toes (Fig. 29). The bones 
 of the limbs are very delicate and thin walled (Fig. 26). The 
 
AIR-BREATHERS OF THE COAL PERIOD. 53 
 
 bony scales are oval, and similar to those of the other species of 
 the genus, but very small (Fig. 31). I suppose it probable that 
 the fragments of skin with imbricated scales represented in Plate 
 .V, Figs. 22, 23, and 24, may have belonged to this species, but 
 I cannot certainly affirm that this was the case. 
 
 In length, ffylonomus Wymani could not have exceeded four or 
 five inches, and its form was thin and slender. It may be 
 questioned whether this little creature was not the young of one 
 of the other species. The form of the vertebrae and teeth would y 
 I think, prevent us from supposing that it stood in this rela- 
 tion to H. Lyelli. To H. adedentatus it bears a stronger resem- 
 blance in these respects, though not sufficient to render specific 
 identity probable ; and the occurrence of so many specimens of 
 the smaller species, without any of intermediate size, renders it 
 likely that it did not attain to any greater dimensions. 
 
 ffylonomus Wymani probably fed on insects and larvae, and 
 searched for these among the vegetable debris of the coal swamps, 
 which would afford to a little creature like this abundant shelter. 
 It occasionally fell a prey to its larger reptilian contemporaries ; 
 for quantities of its tiny bones occur in coprolitic masses probably 
 attributable to Dendrerpeton. It is interesting to find reptilian 
 life represented at this early period, not only by large and formi- 
 dable species, but by diminutive forms, comparable with the smal- 
 lest lizards and newts of the modern world. The fact is parallel 
 with that of the occurrence of several small mammalian species 
 in the mesozoic beds. It will be still more significant in this res- 
 pect if the species of Hylonomus should be found to be truly la- 
 certian rather than batrachian. 
 
54 AIR-BREATHERS OF THE COAL PERIOD. 
 
 EXPLANATION OF PLATE VI, FIGS. 18 TO 31. 
 Hylonomus Wymani. 
 
 Fig. 18 Lower jaw with teeth, magnified. 
 
 " 19 Anterior part of lower jaw more magnified. 
 
 " 20 Portion of maxillary bone with teeth, magnified. 
 
 " 21 Maxillary bone, natural size. 
 
 " 22 Lower jaw, natural size. 
 
 11 23 Vertebrae, natural size. 
 
 " 24 and 25 Vertebrae, magnified. 
 
 " 26 Humerus, natural size and magnified. 
 
 " 27 Rib, natural size and magnified. 
 
 " 28 Pelvic bone, natural size and magnified. 
 
 29 Foot ; the line shows the natural size. 
 
 30 Broken vertebra magnified, showing internal cavity. 
 
 " 31 Bony scales, natural size and magnified. 
 
AIR-BREATHERS OP THE COAL PERIOD. 55 
 
 X. HYLERPETON DAWSONI. 
 Plate VI, Figs. 32 to 46. 
 
 In the more or less laminated material which fills the interior 
 of the erect trees of the Joggins, it often happens that the more 
 distinctly separable surfaces are stained with ferruginous or coaly 
 matter, or with fine clay, so that the fossils which occur on these 
 surfaces, and which would otherwise be more available than those 
 in more compact material, are rendered so obscure as readily to 
 escape observation. This was unfortunately the case with one of 
 the most interesting specimens contained in the last of these trees 
 which I had an opportunity to examine. It consisted of the de- 
 tached bones of a reptile scattered over a surface so blurred and 
 stained that they escaped my notice until most of them were lost ; 
 and I was able to secure only a jaw bone and fragments of the 
 skull, with a few of the other bones. On these fragments Prof. 
 Owen founded 'the genus Hylerpeton and the species named at 
 the head of this article. His description is as follows : 
 
 " This specimen consists of the left ramus of a lower jaw (Fig. 
 32), which has been dislocated from the crushed head, of which 
 the fore end of the left premaxillary is preserved, terminating 
 near the middle of the series of the teeth of the more advanced 
 mandible. A fragment of the left maxillary, which has been se- 
 parated from the premaxillary, overlaps the hinder mandibular 
 teeth. The fore part of the mandible is wanting. The teeth in 
 the remaining part are larger and fewer, in proportion to the jaw- 
 bone, than in Hylonomus or Dendrerpeton. They have thicker 
 and more obtusely terminated crowns ; they are close-set where 
 the series is complete at the fore part of the jaw, and their base 
 appears to have been anchylosed to shallow depressions on the 
 alveolar surface. The shape of what is preserved of the upper 
 jaw affords the only evidence, and not very decisively, that the 
 present fossil is not part of a fish. It inclines the balance, how- 
 ever, to the reptilian side ; and, accepting such indication of the 
 
56 AIR-BREATHERS OF THE COAL PERIOD. 
 
 class-relations of the fossil, it must be referred to a genus of Rep- 
 tilia distinct from those it is associated with in the Nova Scotian 
 coal, and for which genus I would suggest the term Hylerpeton. 
 
 " A small part of the external surface of the dentary bone shows 
 a longitudinally wrinkled and striate or fibrous character. The 
 outer bony wall, broken away from the hinder half of the dentary, 
 shows a large cavity, now occupied by a fine greyish matrix, 
 with a smooth surface, the bony wall of which cavity has been 
 thin and compact. We have here the mark of incomplete ossifica- 
 tion, like that in the skeleton of Archegosaurus. The crushed 
 fore part of the right dentary bone, with remains of a few teeth, 
 is below the left dentary, and exemplifies a similar structure. 
 The teeth slightly diminish, though more in breadth than length, 
 towards the fore part of the series : here there are nine teeth in 
 an alveolar extent of 10 millimeters, or nearly 5 lines. The base 
 of the teeth is longitudinally fissured, but the fissures do not ex- 
 tend upon the exserted crown. In their general characters, the 
 teeth manifest at least as close a resemblance to those of Gano- 
 vephala as of Lacertia or any higher group of Reptilia ; whilst 
 their mode of implantation, with the structure and sculpturing of 
 the bone, weigh in favour of its relations to the lower and earlier 
 order of the cold-blooded Vertebrates." 
 
 I can add to the above description only a few facts obtained 
 from careful examination of other fragments imbedded in the ma- 
 trix. One of these is a portion of a maxillary bone (Fig. 32). 
 It has teeth similar to those of the lower jaw in form (Figs. 34 
 and 35), but the last but one is twice the size of the others, and 
 seems to have been implanted in a deep socket. All of the teeth 
 have large pulp cavities, and the inner surface of the ivory is 
 marked with slight furrows which are represented by ridges on 
 the outer surface of the stony matter filling the pulp cavities 
 (Fig. 36). The ivory of the teeth, however, which is very much 
 coarser than that of the species of Hylonomus, presents in the 
 cross section a simple structure of radiating tubes (Fig. 37). The 
 surface of the cranial bones, of which some fragments remain, is 
 
AIR-BREATHERS OF THE COAL PERIOD. 57 
 
 marked in the same striate manner alluded to above by Prof. 
 Owen (Figs. 42, 43). The microscopic structure of the bone is 
 muca coarser than that of Hylonomus or Dendrerpeton, the cells 
 being larger and in some portions less elongated (Fig. 46). That 
 the creature had stout ribs is shown by the fragments represented 
 in Fig. 40 ; but the vertebrae are represented only by a few 
 bodies of small relative size and perhaps caudal (Figs. 38 and 39). 
 On the same surface was found the foot represented in Fig. 44. 
 It is of small size relatively to the head, and was probably for swim- 
 ing rather than walking. A few ovate bony scales were found 
 with the bones, and probably belonged to this species (Fig. 41). 
 On the whole it seems certain that Hylerpeton must have been 
 generically distinct from the other reptiles found with it, and it is 
 probable that it was of more aquatic habits, swimming rather than 
 walking ; and feeding principally on fish. More perfect speci- 
 mens would however be required in order to warrant any decided 
 statement on these subjects. It is possible, as suggested by Prof. 
 Owen, that the affinities of the animal may be with Archegosau- 
 rus rather than with any of the other coal reptiles ; but I confess 
 that my present impression is that it tends rather toward the 
 genus Hylonomus. It may possibly be a link of connection b- 
 tween the Microsauria and the Archegosauria. 
 
 EXPLANATION OF PLATE VI, FIGS. 32 TO 46. 
 
 Hylerpeton Dawsoni. 
 
 Fig. 32 Portion of maxillary bone with teeth. 
 c 33 Lower jaw and portions of skull. 
 " 34 and 35 Teeth magnified. 
 (( 36 Cast of pulp cavity of a tooth. 
 it a? Cross section of tooth magnified. 
 38 and 39 Bodies of Vertebrae. 
 K 40 Fragments of ribs. 
 41 Bony scale natural size and magnified. 
 " 42 and 43 Surface of bone magnified. 
 44 Foot. 
 
 " 45 Bone of same magnified. 
 46 Section of bone highly magnified, 
 
 H 
 
58 AIR-BREATHERS OP THE COAL PERIOD, 
 
 t 
 
 XL ADDITIONAL REPTILIAN REMAINS. 
 Plate VI, Figs. 47, 48, and 54 to 56. 
 
 Beside the species above described, Mr. 0. 0. Marsh, in 1861,* 
 added a new animal to the Joggins reptilian fauna ; the Eosau- 
 ru Acadianus. The species is founded on two large biconcave 
 vertebrae, in many respects resembling those of Ichthyosaurus, 
 and indicating a reptile of greater size than any hitherto dis- 
 covered in the coal, probably of aquatic habits, and possibly allied 
 to the great Enaliosaurs or sea lizards of the mesozoic rocks. 
 The specimen was found in a bed of shale belonging to group 
 XXVI of my Joggins section, in the upper part of the middle 
 coal measures, and about 800 feet above the bed which has 
 afforded the remains described in previous sections. The beds 
 belong to one of those intervals of shallow water deposition of 
 sediment, which separate the groups of coal beds ; and on one of 
 them I found some years ago the footprints of Dendrerpeton. 
 
 The vertebrae of Eosaurus have been fully and ably described 
 by Mr. Marsh in Silliman's Journal. Agassiz and Wyman regard 
 their affinities as enaliosaurian. Huxley suggests the possibility, 
 founded on his recent discovery of Anthrdcosaurus Russelli, that 
 there may have been I/abyrinthodont batrachians in the coal pe- 
 riod with such vertebrae. However this may be, if the vertebrae 
 were caudal as supposed by Mr. Marsh, since they are about 2$ 
 inches in diameter, they would indicate a gigantic aquatic reptile, 
 furnished with a powerful swimming tail, and no doubt with appa- 
 ratus for the capture and destruction of its prey, comparable with 
 that of Ichthyosaurus. 
 
 In a bed of hard calcareous sandstone, some distance below that 
 which afforded the animal just noticed, there occur great numbers 
 of teeth and scales, referable in part to large sauroid fishes, but 
 perhaps also in part to reptiles. One of these is a remarkable 
 tooth obtained by Sir W. E. Logan in 1843, and represented in 
 
 * The remains were discovered in 1855 though not published till 1861 . 
 
AIK-BREATHERS OF THE COAL PERIOD. 59 
 
 Fig. 47. It resembles externally the teeth of Baphetes, but its 
 structure is almost precisely that of the teeth of the Lepidosteus, 
 or bony pike of the St. Lawrence. Another tooth from the same 
 bed, and wfth a similarly fluted surface, has a more complex laby- 
 rinthic structure, as seen in Fig. 48, which however represents 
 only a small fragment. With these occur large round thin scales 
 like those of Rhizodus, but also wrinkled bony plates resembling 
 that which I have attributed to Baphetes. From the hardness of 
 the rock it is difficult to extract perfect specimens of these re- 
 mains, and no bones other than teeth and dermal scales have 
 been found. 
 
 Under this head may be noticed the coprolitic matter which 
 not infrequently occurs with the remains of reptiles, in the erect 
 trees of the Joggins, and to which reference has already been 
 made in previous sections. This fossil excrement is of a brown 
 or fawn colour, and consists in great part of carbonate, of lime, 
 indicating probably that shells of snails or other mullusks formed 
 a considerable part of the food of the smaller reptiles of the coal 
 swamps. Some portions of it are rilled with small bones appa- 
 rently of Hylonomus Wymani. Other examples contain abun- 
 dance of fragments of chitinous matter referable ia part to Xylo- 
 bius Sigillarice, the millipede of the coal ; and in other instances 
 to insects. Of the latter kind of remains the most interesting is 
 an Eye, represented in Fig. 56. It must have belonged to an in- 
 sect of considerable size, and with highly complex eyes, probably 
 a neuropterous insect. As many as 250 facets are distinguishable 
 in the fragment preserved, and the whole number in each eye 
 may have amounted to 2000. In size and form the facets re- 
 semble those of the eye of a common Canadian dragon fly of the 
 genus Aeschna, but are a little smaller. In this and other copro- 
 lites, though abundance of minute chitinous fragments remain, no 
 others are sufficiently perfect to be recognized. In one coprolitic 
 mass a quantity of thick crust or shell occurs, which under the 
 microscope presents a minutely tubular and laminated appear- 
 ance, resembling that of the shell of a crustacean rather than 
 
60 AIR-BREATHERS OF THE COAL PERIOD. 
 
 any other kind of structure with which I am acquainted. There 
 may have been laud-crabs in the coal period ; but it is perhaps 
 more likely that some one of the larger individuals of Dendrer- 
 peton had been feeding on crustaceans in some poUd or creek, 
 before it fell into the pit in which it was entombed. It is how- 
 ever interesting to observe that no remains whatever of fishes 
 have occurred in any of this coprolite or in the erect trees contain- 
 ing reptile bones, though such remains are very abundant in some 
 of the associated beds. This fact confirms the inference dedu- 
 cible from other considerations, that the ground in which these 
 open pits presented themselves, was not that of a very low swamp, 
 liable to inundation, or very near to the sea or other bodies of 
 water. 
 
 I may notice here certain very remarkable impressions, the 
 origin of which I am at a loss to conjecture, but which may have 
 had some relation to reptiles of the Coal period. They occurred 
 on the surface of a layer of grey sandstone about 60 feet above 
 the bed containing the erect reptiliferous trees. This bed is one 
 of a series of flaggy layers on which occur, with vegetable frag- 
 ments, tracks, possibly of Hylonomus, and rain-marks. The im- 
 pressions now referred to were thus described by me in 1861 : 
 
 " They consist of rows of tranverse depressions, about an inch 
 in length and one-fourth of an inch in breadth. Each trail con- 
 sists of two of these rows running parallel to each other, and 
 about six inches apart. Their direction curves abruptly, and they 
 sometimes cross each other. From their position they were pro- 
 bably produced by a land or fresh-water animal possibly a large 
 Crustacean or gigantic Annelide or Myriapod. In size and gene- 
 ral appearance they slightly resemble the curious Climactichnites 
 of Sir W. E. Logan, from the Potsdam sandstone of Canada." 
 To this I have only to add that the space between the rows of 
 marks is slightly depressed and smoothed, as if with a heavy body, 
 like that of a serpent, trailed along. 
 
 I have given in Fig. 54, as a supplement to the history of Den- 
 drerpeton and Hylonomus, a diagram of the form of the skull and 
 
AIR-BREATHERS OF THE COAL PERIOD. 61 
 
 the character of the dentition, restored from actual specimens. 
 This will serve further to illustrate the descriptions in previous 
 sections. 
 
 In Fig. 65 I have represented a group of scales from the throat 
 of Dendrerpeton, as they lie beside the skull from which the 
 greater part of the details in Fig. 54 are taken. It will be seen 
 that these are elongated, oval, and very closely imbricated in rows 
 diverging in a pinnate manner from a mesial line. They would 
 give much protection, while not deficient in flexibility. It is pro- 
 bable however that Dendrerpeton could breathe by other means 
 than the gulping of air by the contraction of the throat ; and 
 would therefore be less dependent on the action of the gular mus- 
 cles than the modern batrachians. 
 
 EXPLANATION OF PLATE VI, FIGS. 47, 48, AUD 54 TO 56.] 
 Additional Reptilian Remains. 
 
 Fig. 47 Tooth of unknown reptile or fish, natural size, section natu- 
 ral size, and portion of section magnified, showing infold- 
 ing of the enamel and arrangement of the dentine. 
 
 48 Small segment of another tooth similar to the last in form 
 and size, but more complex in the folding of the enamel- 
 
 54 Outer figure Diagram of skull of Dendrerpeton, showing its 
 size and general form, the appearance of the occipital 
 condyles, and the arrangement of the double row of max- 
 illary teeth and of the vomerine teeth. 
 
 " 54 Inner figure Diagram of skull of Hylonomits, showing the 
 arrangement of the single row of maxillary teeth and the 
 patch of palatal teeth. 
 
 55 Bony scales of the throat of Dendrerpeton Acadianum, natural 
 
62 AIR-BREATHERS OP THE COAL PERIOD. 
 
 XII. INVERTEBRATE AIR-BREATHERS. 
 Plate VI., Pigs. 49 to 53, and 56 to 61. 
 
 In addition to the insect whose eye has already been noticed, 
 but two species of land Invertebrates have been recognized in the 
 coal of Nova Scotia. One of these is a snail, Pupa vetusta, the 
 other a gally-worm or millepede, XyloHus sigillarice. They are 
 represented in the figures referred to at the head of this section, and 
 have been fully described in the Journal of the Geological Society 
 of London. 
 
 The first is the oldest known representative of the land 
 snails, and so closely resembles the modern "chrysalis shells" of 
 the genus Pupa, that I have not thought it desirable to refer it to 
 a different genus, though the name Dendropupa has been proposed 
 by Prof. Owen. Mr. J. S. Jeffreys and other eminent concholo- 
 gists, who have seen the shell, concur in the opinion that it is a 
 true Pupa ; so that this genus, like Lingula and Nautilus, extends 
 from the palaeozoic to the modern times. 
 
 It may be described as a cylindrical shell, tapering to the apex, 
 with a shining surface, marked with longitudinal rounded ridges. 
 The whorls are eight or nine, rounded, and the width of each 
 whorl is about half the diameter of the shell. The aperture is 
 rather longer than broad ; but is usually somewhat distorted by 
 pressure. The margin of the lip is somewhat regularly rounded 
 and is reflected outward. There are no teeth, but a slight indica- 
 tion of a ridge or ridges on the pillar lip, which may however be 
 accidental. Length fVths of an inch or a little more. It was 
 first recognized by Dr. Gould of Boston, in specimens obtained by 
 Sir C. Lyell and the writer at the Joggins. 
 
 This little shell is remarkable, not merely for its great antiquity, 
 but also because it is separated by so wide an interval of time 
 from any other known species of its race, there being no other 
 Pulmonate known until we reach the Purbeck beds, and no true 
 land snail until we reach the Tertiary. It is also worthy of remark, 
 that while hundreds of specimens have been found, not only in 
 
AIR-BBEATHEBS OF THE COAL PEBIOD. 63 
 
 the erect reptiliferous trunks but in a bed 121Y feet lower, and 
 separated by twenty-one coal beds, not any other species is found 
 with it. It is very rare in modern times thus to find one species of 
 snail in great abundance without any others. More especially is 
 this so when we can examine, as in this case, not only the decayed 
 trunks in which the creature sheltered itself, but also the beds of 
 mud into which its dead shells were washed. These facts present a 
 striking instance either of that " imperfection of the geological 
 record", of which we hear so much, or of the solitary existence of 
 a single species as a prophetic representative of future things, to 
 be realized long after it had ceased to exist. 
 
 The lower bed, holding shells of Pupa vetusta, just mentioned, 
 is a grey and greyish-blue under-clay, full of stigmarian rootlets, 
 though without any coal or erect trees at its surface. It is 7 feet 
 thick, with sandstone above and below. The shells occur very 
 abundantly in a thickness of about two inches. They have been 
 imbedded entire ; but most of them have been crushed and flat- 
 tened by pressure. They occur in all stages of growth ; the young 
 being, as is always the case in such shells, very different in general 
 form from the adults. This bed is evidently a layer of mud deposited 
 in a pond or creek, which afterward became silted up and carried 
 sigillaroid trees. In modern swamps multitudes of shells occur in 
 such places ; and it is remarkable that in this case a single land 
 shell should alone be found, without any trace of aquatic mollusks. 
 The shells which occur in this bed are filled with the surrounding 
 sediment. Those which occur in the erect Sigillarice, on the 
 other hand, except when they are crushed and flattened, are filled 
 with a deposit of brown calc-spar. I infer from this that the 
 latter when buried contained the animals, and consequently that 
 these lived or sheltered themselves in the hollow trees, as is the 
 habit of many modern land snails. 
 
 The gally-worm of the coal period, Xylobius Sigillarice, must 
 have existed in great numbers, as many layers in the erect treea 
 are full of them. It probably lived in these decaying trunks just 
 as its modern congeners do in similar places. As an air-breathing 
 
64: AIR-BREATHERS OF THE COAL PERIOD. 
 
 animal, and subsisting on vegetable food, it cannot have lived in 
 water, or even in very wet places ; and this is one of the evidences 
 which in this case point to a greater dryness of the coal swamps 
 than has hitherto been supposed probable ; it also shows the resem- 
 blance of the conditions of the areas of coal accumulation to 
 those of modern forests. 
 
 With regard to the affinities of XyloUus, its form and structure 
 render certain its alliance with the Myriapods, and with the chilog. 
 nathous division of them, or the gally-worms ; but it is less certain 
 to which of the families of the recent gally-worms it belongs, if to 
 any of them. I have however little doubt that if it existed as a 
 recent animal, it would go into the tribe Bizonia of Newport, and 
 probably into the family of lulidce, to the typical genus of which 
 it bears a strong resemblance in such points as can be made out. 
 The oldest Myriapod previously known is, I believe, the Geophilus 
 proavus, Miinster, of the Jurassic period*. 
 
 EXPLANATION OF PL. VI, FIGS. 47 TO 53, AND 56 TO 61. 
 Invertebrate Air-Breathers. 
 
 Fig. 49. Pupa Vetusta, natural size. 
 it so. magnified. 
 <l 51. Pupa Vetusta, apex magnified. 
 (t 52. " sculpture of surface magnified. 
 53.. " cellular structure of shell highly magnified. 
 56. Eye of an Insect, natural size and magnified, and three ocelli 
 
 highly magnified. 
 
 K 57. Xylobius Sigillarue, Anterior segments magnified. 
 58. " natural size. 
 
 59. " part of one of the posterior segments 
 
 magnified. 
 
 go. " " caudal extremity magnified. 
 
 61. " " head magnified, showing the eyes. 
 
 .. I I I .!. .... . I .. I. 
 
 Pictet, Palaeontologie, Vol. 11, p. 405. 
 
AIR-BREATHERS OF THE COAL PERIOD. 65 
 
 XIII. CHARACTERS OF THE ANIMALS DESCRIBED IN THIS PAPER. 
 
 To facilitate comparisons, I propose in this section to give an 
 abstract of the leading structural points which may serve to dis- 
 tinguish the animals described in this paper from each other, and 
 from such new species as may be discovered either in Nova Scotia 
 or elsewhere. The characters given must necessarily be incom- 
 plete, and I shall confine myself to points distinctly ascertained 
 and likely to be met with in any additional specimens which 
 may be discovered. 
 
 Province. VERTEBRATA. 
 
 Class. REPTILIA. 
 Order. MICROSAURIA. 
 
 Genus. HYLONOMU&, 
 
 Reptiles or batrachians ; with simple teeth in one series ; bi- 
 concave vertebrae with arches anehylosed to them ; ribs long and 
 bent; limbs developed for walking; cranial bones smooth or 
 nearly so ; body protected below with oval or ovate bony scales, 
 and above with horny scales and other appendages. 
 
 1. Hylonomus Lyetti, Dawson. Teeth elongated, conical, 
 thirty-six in each side of the jaw; larger toward the anterior 
 part of the lower jaw ; length of lower jaw ,7 inch ; limbs well 
 developed, especially the posterior pair ; bony scales oval ; body 
 above with imbricated horny scales, and rows of angular and 
 bristly points. 
 
 2. Hylonomus aciedentatus, Dawson. Teeth of maxillary and 
 mandible thick wedge form, or nearly round at base and flattened 
 to an edge at top. Teeth of intermaxillaries cylindric, bluntly 
 pointed, and with spiral furrows at the point. Number of teeth 
 about forty on each side of jaw ; length of lower jaw about 1 inch. 
 Size more than twice that of H. Lyelli. Dermal covering so far 
 as known, similar, but the parts large in proportion. 
 
 3. Hylonomus Wymani, Dawson. Teeth obtusely conical, about 
 
 I 
 
66 AIR-BREATHERS OF THE COAL PERIOD. 
 
 twenty in each side of the jaw; length of lower jaw about .25 
 inch. Vertebrae elongated ; size much smaller than that of H. 
 Lyelli. Bony scales small and rounded, body above probably 
 clothed in imbricated horny scales. 
 
 Order. LABYRINTHODONTIA. 
 Genus. BAPHETES. 
 
 Baphetes planiceps, Owen. Teeth conical, hooked, striated 
 longitudinally, and with inflected and convoluted cement ; in two 
 series ; the inner of larger size. Cranial bones much corrugated. 
 Head broad ; breadth in front of orbits 6 inches ; length from 
 this line to front of snout 3 J inches. Probably a dermal covering 
 of corrugated bony scales. 
 
 Genus. DENDRERPETW. 
 
 Batrachians with a double series of teeth ; the outer simple and 
 flattened conic, the inner conical with inflected folds of cement. 
 Teeth also on the vomer. Bones of skull corrugated ; body pro- 
 tected below with long ovate or rhomboid bony scales, and above 
 with imbricated horny scales. Form elongated, fore limbs largest, 
 tail natatory, vertebrae biconcave, neural arches and bodies 
 ossified. 
 
 1. Dendrerpeton Acadianum, Owen. Inner teeth straight 
 conical ; outer teeth short and obtuse. Length of head 2.75 inches, 
 breadth at orbits about 2 inches, distance of orbits .7 inch. 
 Length one to two feet. 
 
 2. D. Oweni, Dawson. Teeth slender and hooked, and cement 
 of inner teeth more perfectly inflected. Length of skull 1.2 inch, 
 distance of orbits about .5 inch ; length one foot or less. 
 
 Order. ARCHEGOSAURIA ? 
 Genus. HYLERPETON. 
 
 Hylerpeton Dawsonij Owen. Teeth simple, bluntly conical, 
 with large pulp cavity ; about 13 in one side of the jaw. Two 
 of the anterior teeth of the upper jaw twice as large as the others, 
 
AIR-BKEATHERS OF THE COAL PERIOD. 67 
 
 and deeply sunk in the jaw. Length of lower jaw 1.3 inch 
 Bones of skull puncto-striate. Limbs unknown, probably natatory. 
 
 SKDIS INCBET^E. 
 Genus. E OSAURUS. 
 
 Eosaurus Acadianus, Marsh. Known by two biconcave ver- 
 tebrae 2.4 inches in diameter and much resembling the caudal 
 vertebrae of Ichthyosaurus see paper by Mr. Marsh, Silliman's 
 Journal, vol. xxxrv. 
 
 Province. ARTICULATA. 
 
 Sub Class. MYRIAPODA. 
 Order. CHILOGNATHA. 
 
 Genus. XYLOBIUS. 
 
 Xylobius Sigillarice, Dawson. Body crustaceous, elongate, 
 one to two inches in length, articulate ; when recent, cylindrical or 
 nearly so, rolling spirally. Feet small, numerous ; segments 30 or 
 more ; anterior segments smooth, posterior with transverse 
 wrinkles, giving a furrowed appearance. In some specimens 
 traces of a series of lateral pores or stigmata. Labrum? quadri- 
 lateral, divided by notches or joints into three portions. Mandibles 
 two-jointed, last joint ovate and pointed. Eyes ten or more on 
 each side. 
 
 ProwVice. MOLLUSCA. 
 Class. GASTEROPODA. 
 Order. PULMONATA. 
 
 Genus. PUPA. 
 
 Pupa Vetusta, Dawson. Cylindrical, tapering toward the 
 apex ; surface shining, minutely marked with longitudinal ridges ; 
 whorls 8 or 9, rounded, width of each equal to half the diameter 
 of the shell ; aperture rather longer than broad ; outer lip regu- 
 larly rounded and somewhat reflected ; pillar lip straightened above, 
 rounded below. Edentulous or with faint ridges on columella? 
 Length .3 inch or a little more. 
 
68 AIR-BREATHERS OF THE COAL PERIOD. 
 
 
 
 XIV. CONCLUDING REMARKS. 
 
 Having finished the work which I proposed to myself, in illus- 
 tration of the air-breathers of the coal period in Nova Scotia, iff 
 now remains to mention a few general thoughts which have arisen 
 in connection with the animals which have been described. 
 
 I have endeavored, in the frontispiece, to present to the eye the 
 forms and attitudes of these creatures. In doing so as little lati- 
 tude as possible has been allowed to the imagination, and the 
 structural points indicated by the bones and skin actually found y 
 have been adhered to as closely as practicable. On the left hand 
 Baphetes planiceps is seen emerging with a ganoid fish in its- 
 jaws. Next Dendrerpeton Acadianum is represented slowly 
 walking up the inclined shore, and leaving its hand-like footprints 
 thereon. A little farther up Hylonomus LyelU is leaping in pur- 
 suit of an insect, and Hylonomus Wymani stands a little more in 
 the foreground, while Hylerpeton Dawsoni is disporting itself in 
 the water in front. I am quite aware that the form and action 
 given to Hylonomus are at variance with the views of its nature, 
 which would ally it with Archegosaurus ; but, as stated above, I 
 cannot refuse my belief to the testimony of the bones themselves, 
 which prove a development of the hind limbs not likely to have 
 been associated with an elongated body and natatorial tail, and 
 pointing to saltatory motion on land, and perhaps frog-like swim- 
 ming in the water. In the middle ground of the picture I have 
 placed a bank of soil, showing a section of a hollow trunk similar 
 in situation to those in which the reptile bones of the Joggins 
 occur, and on this bank and in the distance, I have endeavored to 
 give some of the chavacteristic forms of the vegetation of the 
 period : Ferns, Cordaites, Sigillaria, Lepidendron, Lepidophloios r 
 and Calamites. 
 
 It has recently been a favorite view with some writers on this 
 subject, that coal beds may have been formed in shallow salt water, 
 and that SigiUarice may have grown in such places, like man- 
 groves. It will be seen from the frontispiece, that I do not believe 
 
AIR-BREATHERS OF THE COAL PERIOD. 69 
 
 in this theory of the formation of coal, but on the contrary adhere 
 to the opinion which I have formerly maintained, that the coal beds 
 and under-clays are of the nature of peaty soils. In no part of 
 the world are the coal measures better developed or more fully 
 exposed than in the coast sections of Nova Scotia and Cape Breton ; 
 and in these, throughout their whole thickness, no indication has 
 been found of any of the marine fossils of the lower carboniferous 
 limestone. Abundant remains of fishes occur, but these may have 
 frequented estuaries, streams and ponds, and the greater part of 
 them are small ganoids which, like the modern Lepidosteus and 
 Amia, may have been specially fitted by their semi-reptilian res* 
 piration, for the impure waters of swampy regions. Bivalve 
 molluscs also abound ; but these are all of the kinds to which I 
 have given the generic name Naiadites, and Mr. Salter those of 
 AntJvracomya and Anthracoptera. These shells are all distinct 
 from any known in the marine limestones. Their thin edentu- 
 lous valves, their structure consisting of a wrinkled epidermis, a 
 thin layer of prismatic shell and an inner layer of sub-nacreous shell 
 composed of obscure polygonal cells, all remind us of the Anodons 
 and Unios.* A slight notch in front, noticed by Salter, as possibly 
 byssal, concurs with their mode of occurrence in rendering it prob- 
 able that,like mussels in modem estuaries, they attached themselves 
 to floating or sunken timber. They are thus removed, both in 
 structure and habit, from truly marine species ; and if not actually 
 of the family Uhionidce, must have been fresh-water or brackish - 
 water mussels closely allied to this family. The crustaceans 
 (Eurypterus,Diplostylus,Cyprids,) and the worm shell (Spirorbis)^ 
 
 * The microscopic structure of these shells is well preserved, and 
 presents some differences of detail which I hope at a future time to 
 illustrate. 
 
 t The idea of some Palseobotanists, that these so-called Spirorbes are 
 fossil parasitic plants, is obviously a mistake. They are calcareous 
 shells, and present under the microscope a prismatic cellular structure, 
 with numerous minute tubuli, in the manner of the shells of modern 
 Serpula and Spirorbes. In Nova Scotia I have seen Estheria only in 
 the lower coal formation. 
 
70 AIR-BREATHERS OF THE COAL PERIOD. 
 
 found with them, are not necessarily marine, though some of them 
 belonged probably to brackish water, and they have not vet been 
 found in those carboniferous beds deposited in the open sea. There is 
 thus in the whole thickness of the middle coal measures of Nova 
 Scotia, a remarkable absence at least of open sea animals ; and if, 
 as is quite probable, the sea inundated at intervals the areas of 
 coal accumulation, the waters must have been shallow and to a 
 great extent land-locked, so that brackish-water rather than marine 
 animals inhabited them. 
 
 On the other band, there are in these coal measures, abundant 
 evidences of land surfaces ; and sub-aeriel decay of vegetable mat- 
 ter in large quantity is proved by the occurrence of the mineral 
 charcoal of the coal itself, as I have elsewhere shown.* The erect 
 trees which occur at so many levels, also imply sub-aerial decay. A 
 tree imbedded in sediment and remaining under water, could not 
 decay so as to become hollow and deposit the remains of its wood 
 in the state of mineral charcoal within the hollow bark. Yet 
 this is the case with the greater part of the erect sigillarisB which 
 occur at more than 20 levels in the Joggins section. Nor could 
 such hollow trunks become repositories for millipedes, snails and 
 reptiles, if under water. On the other hand, if, as seems neces- 
 sary to explain the character of the reptiliferous erect trees, these 
 remained dry or nearly so in the interior, this would imply not 
 merely a soil out of water, but comparatively well drained ; as 
 would indeed always be the case, when a flat resting on a sandy 
 subsoil was raised several feet above the level of the water. 
 Farther, though the peculiar character of the roots of Sigillarice 
 and Calamites may lend some countenance to the supposition that 
 they could grow under water or in water-soaked soils, this 
 will not apply to coniferous trees, to ferns, and other plants, 
 which are found under circumstances which show that they grew 
 with the Sigillarice. 
 
 In the coal measures of Nova Scotia, therefore, while marine 
 
 * Journal of Geological Survey, vol. XV. 
 
AIR-BREATHERS OP THE COAL PERIOD. 71 
 
 conditions are absent, there are ample evidences of fresh-water or 
 brackish-water conditions, and of land surfaces, suitable for the 
 air-breathing animals of the period. Nor do I believe that the 
 coal measures of Nova Scotia were exceptional in this respect. It 
 is true that in Great Britain evidences of marine life do occur in 
 the coal measures ; but not, so far as I am aware, in circumstances 
 which justify the inference that the coal is of marine origin. Al- 
 ternations of marine and land remains, and even mixtures of 
 these, are frequent in modern submarine forests. When we find, 
 as at Fort Lawrence in Nova Scotia, a modern forest rooted in 
 upland soil forty feet below high-water mark, * and covered with 
 mud containing living Tellinas and My as, we are not justified in 
 inferring that this forest grew in the sea. We rather infer that 
 subsidence has occurred. In modern salt marshes it is not un- 
 usual to find every little runnel or pool full of marine shellfish, 
 while in the higher parts of the marsh land plants are growing ; 
 and in such places the deposit formed must contain a mixture of 
 land plants and marine animals with salt grasses and herbage 
 the whole in situ.\ 
 
 These considerations serve, I think, to explain all the apparently 
 anomalous associations of coal plants with marine fossils ; and I do 
 not know any other arguments of apparent weight that can 
 be adduced in favor of the marine origin of coal, except such as 
 are based on misconceptions of the structure and mode of growth 
 of sigillaroid trees and of the stratigraphical relations of the coal 
 itself.J It is to be observed, however, that while I must maintain 
 
 * Journal of Geological Society, vol. XI, 
 
 f In the marshes at the mouth of Scarborough River, in Maine, chan- 
 nels not more than a foot wide, and far from the sea, are full of Mussels 
 and Myae ; and in little pools communicating with these channels there 
 are often many young Limuli, which seem to prefer such places, and the 
 cast off shells and other remains of which may become imbedded in 
 mud and mixed with land plants, just as in the shales of the coal mea- 
 sures. 
 
 t It is unfortunate that few writers on this subject have combined with 
 the knowledge of the geological features of the coal, a sufficient acquain- 
 
72 AIR-BREATHERS OF THE COAL PERIOD. 
 
 the essentially terrestrial character of the ordinary coal and of its 
 plants, I have elsewhere admitted that cannel coals and earthy 
 bitumen present evidences of sub-aquatic deposition ; and have 
 also abundantly illustrated the facts that the coal plants grew on 
 swampy flats, liable not only to river inundations, but also to 
 subsidence and submergence.* In the oscillation of these condi- 
 tions it is evident that Sigillarice and their contemporaries must 
 often have been placed in conditions unfavorable or fatal to them, 
 and when their remains are preserved to us in these conditions, 
 we may form very incorrect inferences as to their mode of life. 
 Farther, it is be observed that the conditions of submergence and 
 silting up which were favorable to the preservation of specimens of 
 Sigillarioe as fossils, must have been precisely those which 
 were destructive to them as living plants ; and on the contrary that 
 the conditions in which these forests may have flourished for cen- 
 turies, must have been those in which there was little chance of 
 their remains being preserved to us, in any other condition at 
 least than that of coal, which reveals only to careful microscopic 
 examination the circumstances, whether aerial or aquatic, under 
 which it was formed. 
 
 It is also to be observed that, in conditions such as those of the^ 
 coal-formation, it would be likely that some plants would be 
 
 tance with the phenomena of modern marshes and swamps, and with tha 
 conditions necessary for the growth of plants such as those of the coal. 
 It would be easy to show, were this a proper place to do so, that the 
 " swells," " rock-faults," splitting of beds, and other appearances of 
 coal seams, quite accord with the theory of swamp accumulation ; that 
 the plants associated with Sigillarice could not have lived with their 
 roots immersed in salt water ; that the chemical character of the under- 
 clays implies drainage and other conditions impossible under the sea ; 
 that the composition and minute structure of the coal are incompatible 
 with the supposition that it is a deposit from water, and especially from 
 salt water ; and that it would be more natural to invoke wind-driftage as 
 a mode of accumulation for some of the sandstones, than water-driftage 
 for the formation of the coal. 
 * Journal of Geol. Socy., vols. X and XV and " Acadian Geology." 
 
AIR-BREATHERS OP THE COAL PERIOD. 73 
 
 -specially adapted to occupy newly emerged flats and places liable 
 to inundation and silting up. I believe that many of the 
 SigillaricB, and still more eminently the Calamites, were suitable to 
 such stations. There is direct evidence that the nuts of Sigillarice 
 (Trigonocarpa) were drifted extensively by water over submerged 
 flats of mud. Many Cardiocarpa were winged seeds which may 
 have drifted in the air. The Calamites may, like modern Equise- 
 ta, have produced spores with elaters capable of floating them in 
 the wind. One of the thinner coals at the Joggins is filled with 
 spores or spore-cases that seem to have carried hairs on their 
 surfaces, and may have been suited to such a mode of dissemina- 
 tion. I have elsewhere proved that at least some species of Cala- 
 mites, were by their mode of growth admirably fitted for growing 
 amid accumulating sediment and for promoting its accumulation. 
 
 These and other facts to be ascertained only by a careful and 
 minute study of the coal formation and its fossils, are essential to 
 a right understanding of the complicated conditions involved in 
 the growth of these great deposits ; and notwithstanding the im- 
 mense mass of facts which has been collected, there is still no de- 
 partment of geology more encumbered with crude hypotheses and 
 hasty generalizations, than that which relates to the history of the 
 carboniferous period. 
 
 The reptiles of the coal formation are probably the oldest known 
 to us, and possibly, though this we cannot affirm, the highest pro- 
 ducts of creation in this period. Supposing, for the moment, 
 that they are the highest animals of their time, and what i& 
 still less likely, that those which we know are a fair average of the 
 rest, we have the curious fact that they are all carnivorous, and 
 the greater part of them fitted to find food in the water as well as 
 on the land. The plant feeders of the period, on the land at least, 
 are all invertebrates, as snails, millepedes, and perhaps insects. 
 The air-breathing vertebrates are not intended to consume the 
 exuberant vegetable growth, but to check the increase of its ani- 
 mal enemies. Plant life would thus seem to have had in every 
 way the advantage. The millepedes probably fed only on roots 
 
 E 
 
74 AIR-BREATHERS OF THE COAL PERIOD. 
 
 and decaying substances the snails on the more juicy and succu- 
 lent plants growing in the shadow of the woods. While, more- 
 over, the vegetation of the coal swamps was most abundant, it 
 was not, on the whole, of a character to lead us to suppose that it 
 supported many animals. Our knowledge of the flora of the coal 
 swamps is sufficiently complete to exclude from them any abund- 
 ance of the higher phaenogamous plants. We know little, it is 
 true, of the flora of the uplands of the period ; but when we speak 
 of the coal formation land, it is to the flats only that we refer. The 
 foliage of the plants on these flats, with the exception of that of 
 the ferns, was harsh and meagre, and there seem to have been no 
 grasses or other nutritious herbaceous plants. These are wants 
 of themselves likely to exclude many of the higher forms of her- 
 bivorous life. On the other hand there was a profusion of large 
 nut-like seeds, which in a modern forest would probably have 
 afforded subsistence to squirrels and similar animals. The pith 
 and thick soft bark of many of the trees must at certain seasons 
 have contained much nutritive matter, while there was certainly 
 sufficient material for all those insects whose larvae feed on living 
 and dead timber, as well as for the creatures that in turn prey on 
 them. It is remarkable that, perhaps with the exception of a 
 very few European insects, no animals fitted to avail themselves of 
 these vast stores of food have been discovered in the coal. The 
 question : " What may have fed on all this vegetation ?" was never 
 absent from my mind in all my explorations of the Nova Scotia 
 coal sections; but no trace of any creature other than those already 
 mentioned has ever rewarded my search. In Nova Scotia it would 
 seem that a single snail and a single gally-worm were the sole links 
 of connection between the plant creation and air-breathing verte- 
 brates. Is this due to the paucity of the fauna, or the imperfec- 
 tion of the record ? The fact that a few erect stumps have revealed 
 nearly all the air-breathers yet found, argues strongly for the latter 
 cause ; but there are some facts bearing on the other side. 
 
 Our gally-worm, if, like its modern relatives, hiding in crevices 
 of wood in forests, was one of the least likely animals to be found 
 
AIR-BREATHERS OF THE COAL PERIOD. 75 
 
 in aqueous deposits. The erect trees gave it its almost sole chance of 
 preservation. Pupa vetusta is a small species, and its shell very 
 thin and fragile, while it probably lived among thick vegetation. 
 Further it occurs in great abundance in the sigillaria stumps, and 
 also in a bed separated from these by a thickness of 1217 feet, 
 including 21 coal seams, having an aggregate thickness of about 
 20 feet, 3 beds of bituminous limestone of animal origin, and per- 
 haps 20 beds holding Stigmaria in situ,or erect Sigillarice and Cala- 
 mites. The lapse of time implied by this succession of beds, many of 
 them neccessarily of very slow deposition, must be very great, though 
 it would be mere guess work to attempt to resolve it into years. 
 Yet long though this interval must have been, Pupa vetusta lasted 
 without one iota of change through it all ; and more remarkable 
 still, was not accompanied by any other mollusk of its family. 
 Where so many specimens occur, and in situations so diverse, 
 without any additional species, the inference is strong that no 
 other of similar habits existed. If in any of those sub-tropical 
 islands, whose climate and productions somewhat resemble those 
 of the coal period, after searching in and about decaying trees, and 
 also on the bars upon which rivers and lakes drifted their bur- 
 dens of shells, we should find only a single species, but this in 
 very great numbers, we would surely conclude that other species, 
 if present, were very rare. 
 
 Again, footprints referrible to Dendrerpeton occur in the lower 
 coal measures below the marine limestones, in the middle coal 
 measures, and in the upper coal formation, separated by a thick- 
 ness of beds which may be estimated at 15,000 feet, and certainly 
 representing a vast lapse of time. Did we know the creature by 
 these impressions alone, we might infer its continued existence for 
 all this great length of time ; but when we also find its bones in 
 the principal repositories of reptile remains, and in company 
 with the other creatures found with it, we satisfy ourselves that of 
 them all it was the most likely to have left its trail in the mud flats, 
 "We thus have reason to conclude that it existed alone during 
 this period, in so far as its especial kind of habitat was con-* 
 
76 AIR-BREATHERS OF THE COAL PERIOD. 
 
 cerned ; though there lived with it other reptiles, some of which, 
 haunting principally the woods, and others the water, were less- 
 likely to leave impressions of their footprints. These may be but 
 slight indications of truth, but they convey strong impressions of 
 the persistence of species, and also of the paucity of species belong- 
 ing to these tribes at the time. 
 
 Every fact of this kind is at present regarded in its bearings 
 on the probable origin of species, and cm the questions of indepen- 
 dent creation or of derivation by natural selection, or by some 
 other secondary law. Naturalists have set themselves to discover 
 the philosopher's stone which can transmute the viler into the more- 
 exalted species. They will probably fail as others have failed be- 
 fore, but may at least hope to elicit some law of succession or 
 occurrence of living creatures^ and to settle more clearly than 
 heretofore what should be regarded as natural species, as distinct 
 from mere races and varieties. It may perhaps be found, after 
 all, that the question whether the creative force manifested itself 
 in calling certain species into existence from nothing, from dead 
 matter, or from previously organized matter, whether by an instant 
 and miraculous act, by more sudden natural change, or by slow and 
 gradual processes, is insoluble by us;, or that all or many of these 
 modes may have been concerned in? making living beings what 
 they are ; but of this every sound thinker must be convinced, that 
 if not originating in distinct creative acts, species as we have them 
 must be due to causes vastly more recondite and complex than the 
 present advocates of derivation suppose. Nor can even the trans- 
 mutationist altogether get rid of the miracle of creation ; though 
 he may push it back to as great a distance as possible. Some crea- 
 tive force must always precede law, and this even when the 
 theorist goes so far as to derive all things from a concourse of 
 atoms ; or, more venturous still, dispenses even with atoms, and 
 resolves ail that he knows into an aggregate of conflicting yet mutu- 
 ally convertible forces. It is scarcely to be supposed that any 
 member even of this last school, will choose to plunge into the 
 two-fold absurdity of supposing that forces are themselves pro- 
 
AIR-BREATHERS OF THE COAL PERIOD. 7T 
 
 duced by nothing but the law of their own action, and produce 
 all things by their action on nothing but themselves. 
 
 If we could affirm that the air-breathers of the coal period 
 were really the first species of their several families, they might 
 acquire additional interest by their bearing on this question of origin 
 of species. We cannot affirm this ; but it may be a harm- 
 less and not uninstructive play of fancy to suppose for a moment 
 that they actually are soj and to inquire on this supposition as to 
 the mode of their introduction. Looking at them from this point 
 of view, we shall first be struck with the fact that they belong to 
 all of the three great leading types of animals which include our 
 modern air-breathers the Vertebrates, the Articulates, and the 
 Mollusks. This at once excludes the supposition that they can 
 all have been derived from each other, within the limits of the 
 coal period. No transmit tationist can have the hardihood to as- 
 sert the convertibility, by any direct method, of a snail into a 
 millipede, or of a millipede into a reptile. The plan of structure 
 in these creatures is not only different but contrasted in its most es- 
 sential features. It would be far more natural to suppose that these 
 animals sprang from aquatic species of their respective types* 
 We should then seek for the ancestors of the snail in aquatic 
 gasteropoda, for those of the millipede in worms or crustaceans, 
 and for those of the reptiles in the fishes of the period. It would 
 be easy to build up an imaginary series of stages, on the principle 
 of natural selection, whereby these results might be effected; but 
 the hypothesis would be destitute of any support from fact, and 
 would be beset by more difficulties than it removes. Why 
 should the result of the transformation of water anails breathing by 
 gills be a Pupa ? Would it not much more likely be an Auricula 
 or a Lirrmeal It will not solve this difficulty to say that the 
 intermediate forms became extinct and so are lost. On the con- 
 trary they exist to this day, though they were not, in so far as we 
 know, introduced so early. But negative evidence must not be 
 relied on ; the record is very imperfect, and such creatures may 
 have existed though unknown to us. It may be answered that 
 
78 AIR-BREATHERS OF THE COAL PERIOD. 
 
 they could not have existed in any considerable numbers, else 
 some of their shells would have appeared in the coal formation 
 beds, so rich in crustaceans and bivalve mollusks. Further, the 
 little Pupa remained unchanged during a very long time, and 
 shows no tendency to resolve itself into anything higher or to 
 descend to anything lower. Here, if anywhere, in what appears 
 to be the first introduction of air-breathing invertebrates, we should 
 be able to find the evidences of transition from the gills of the 
 prosobranchiate and the crustacean to the air-sac of the pulmonate 
 and the tracheae of the millipede. It is also to be observed that 
 many other structural changes are involved r the aggregate of 
 which makes a pulmonate or a millipede different in every par- 
 ticular from its nearest allies among gill-bearing gasteropoda or 
 crustaceans. 
 
 It may be said however that the links of connection between 
 the coal reptiles and the fishes are better established. All the 
 known coal reptiles have leanings to the fishes in certain charac- 
 ters ; and in some, as in Archegosaurus, these are very close. Still 
 the interval to be bridged over is wide, and the differences 
 are by no means those which we should expect. Were the prob- 
 lem given to convert a ganoid fish into an Arckegosaurus or Den- 
 drerpeton, we should be disposed to retain unchanged such char- 
 acters as would be suited to the new habits of the creature, and 
 to change only those directly related to the objects in view. We 
 should probably give little attention to differences in the arrange- 
 ment of skull bones, in the parts of the vertebrae, in the external 
 clothing, in the microscopic structure of the bone, and other 
 peculiarities for serving similar purposes by organs on a different 
 plan, which are so conspicuous so soon as we pass from the fish to 
 the batrachian. It is not in short an improvement of the organs of 
 the fish that we witness so much as the introduction of new organs. 
 The foot of the batrachian, bears perhaps as close a relation to 
 the fin of the fish as the screw of one steamship to the paddle wheel 
 of another, or as the latter to a carriage wheel ; and can be just 
 
AIR-BREATHERS OF THE COAL PERIOD. 79 
 
 as rationally supposed to be not a new instrument but the old 
 one changed. 
 
 Again, our reptiles of the coal do not constitute a continuous 
 series, nor is it possible that they can all, except at widely different 
 times, have originated from the same source. To suppose that 
 Hylonomus grew out of Dendrerpeton or BapJietes, and Eosaurus 
 out of either, startles us almost as much as to suppose that BapJietes 
 grew out of Rhizodus, or Hylonomus out of Palceoniscus. It 
 either happened, for some unknown reason, that many kinds of 
 fishes put on the reptilian guise in the same period, or else the 
 vast lapse of ages required for the production of a reptile from 
 a fish, must be indefinitely increased for the production of many 
 dissimilar reptiles from each other ; or on the other hand we 
 must suppose that the limit between the fish and reptile being 
 once overpassed, a facility for comparatively rapid changes 
 became the property of the latter. Either supposition would, I 
 think, contradict such facts bearing on the subject as are known 
 to us. 
 
 We commenced with supposing that the reptiles of the coal 
 might possibly be the first of their family, but it is evident from 
 the above considerations, that on the doctrine of natural selection, 
 the number and variety of reptiles in this period would imply that 
 their predecessors in this form must have existed from a time 
 earlier than any in which even fishes are known to exist ; so that 
 if we adopt any hypothesis of derivation, it would probably be 
 necessary to have recourse to that which supposes at particular 
 periods a sudden and as yet unaccountable transmutation of one 
 form into another ; a view which in its remoteness from anything 
 included under ordinary natural laws, does not materially differ 
 from that currently received idea of creative intervention, with 
 which, in so far as our coal reptiles can inform us, we are for 
 the present satisfied. 
 
 There is one other point which strikes the naturalist in consid- 
 ering these animals, and which has a certain bearing on such hy- 
 pothesis. It is the combination of various grades of reptilian types 
 
$0 ORIGIN OP ERUPTIVE AND PRIMARY ROCKS. 
 
 in these ancient creatures. It has been well remarked by Hugh 
 Miller, and more fully by Agassiz, that this is characteristic of 
 the first appearance of new groups of animals. Now selection, 
 as it acts in the hands of the breeder, tends to specialization j and 
 natural selection, if there is such a thing, is supposed to tend in 
 the same direction. But when some distinctly new form is to be 
 introduced, an opposite tendency seems to prevail, a sort of aggre- 
 gation in one species of characters afterward to be separated and 
 manifested in distinct groups of creatures. The introduction of 
 such new types also tends to degrade and deprive of their higher 
 properties previously existing groups of lower rank. It is easy 
 to perceive in all this, law and order, in that higher sense in which 
 these terms express the will and plan of the Supreme Mind, but 
 not in that lower sense in which they represent the insensate 
 operation of blind natural forces. 
 
 Humble though the subjects of this paper are, we see in them 
 the work of Supreme Intelligence, introducing new types 
 upon the scene and foreshadowing in them those higher forms 
 afterward to be created. It is this, their Divine origin, and the 
 light which they throw on the plan and order of the creative 
 work, of which we ourselves form a part, that gives them all 
 their interest to us. They are the handiwork of our Father and 
 our God, traces of his presence in primeval ages of the earth, 
 evidences of the unity of his plan and pledges of its progressive 
 nature ; adding their feeble voices to the testimony of revelation 
 in respect to the history of creation in its earlier stages, and to 
 the carrying on of that plan which still involves the extinction of 
 many things from the present world, and the elevation of others 
 into new and glorious manifestations. Their place in the system 
 of nature and in the order of the world's progress, their uses in 
 their own time and their relations to other beings as parts of the 
 great cosmos, are the points that chiefly interest us : and if any 
 one desires to understand more in detail, how they were created, 
 we wish him all success in his inquiries, but warn him not to 
 suppose that this great mystery is to be solved by a reference 
 
AIR-BREATHERS OF THE COAL PERIOD. 81 
 
 merely to material agencies, apart from that Spiritual Power 
 who is the essence of forces, the-srigin of laws. 
 
 While these sheets were passing through the press, I have for 
 the first time been enabled to study Von Meyer's plates of the 
 coal reptiles of Germany* They confirm my previous impression 
 of the generic and probably family distinctness of Dendrerpeton and 
 Hylonomus from Archegosaurus. The former of the two genera 
 named is however that which approaches most nearly to Von 
 Meyer's genus. The arrangement of the teeth in A. latirostris 
 much resembles that in Dendrerpeton, and the scales on the 
 throat and belly are similar in form and arrangement. The form 
 of the skull, and the proportions of its boneSj are, however, quite 
 different in the two genera. The vertebras of Dendrerpeton are 
 also much more perfectly ossified, its ribs very much larger and 
 more bent, and its limbs much larger and adapted for supporting 
 the body on the land. Archegosaurus must have been in all 
 respects more ichthyoid and aquatic than any of the species of 
 Dendrerpeton or Hyhnomus. 
 
 The skull figured by Von Meyer Under the name of Sdero- 
 cephalus Hauseri, may have belonged to an animal more nearly 
 allied to Dendrerpeton than were the species of Archegosaurus. 
 
 If animals of the type of Archegosaurus existed in the coal 
 period in Nova Scotia, their remains would not be likely to occur 
 in such repositories as the erect trunks of Sigillarise, but only in 
 strictly sub-aqueous deposits. 
 
PL.l 
 
 FOOTPRINTS 
 
PL.H 
 
PI.I11 
 
 HEOTRERPETOH A.GADIANTJM.. 
 
PL. IV. 
 
 DENDREUPETON 
 
 n & Homy S c ale s fegs ^2 .&,c j 
 
PL.V 
 
 HYLO^TOMUS LYELLI . 
 

FL.Yl 
 
BY THE SAME AUTHOR: 
 
 ACADIAN GEOLOGY; 
 
 AN ACCOUNT OF THE 
 
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 AND 
 
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 One Vol. 12mo. cloth, pp. 458. Illustrated by many. Woodcut?, and by 
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