AIR-BREATHERS OP THE COAL PERIOD. 7 



raped. It may have been some species of Hylonomus. On the 

 whole, these footprints differ from those found by Dr. King in 

 Pennsylvania ; but they 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 preservation of portions of their skeletons. 



The study of these impressions 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- 

 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. 



III. Baphetes planiceps. 



Plate II. 



In the summer of 1851, I had occasion to spend a day at the 

 Albion mioes; 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. 



