88 AIR-BREATHERS OF THE COAL PERIOD. 



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- 

 tained from the interior of erect Sigillaria?, 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 hoi- " 

 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 



* See a paper by the author, on the structures of coal ; Journal of 

 the Geological Society, Vol. xv ; also supplement to Acadian Geology. 



