278 THE OLDEST AIR-BREATHERS 



of course, of very rare occurrence, and in point of fact we 

 know only one set of beds at the South Joggins in which such 

 remains so preserved occur ; nor is there, so far as I am aware, 

 any other known instance elsewhere. Even in the beds in 

 question only a portion of the trees, about fifteen in thirty, 

 have afforded animal remains. We have, however, thus been 

 enabled to obtain specimens of a number of species which 

 would probably otherwise have been unknown, being less 

 likely than others to be preserved in properly aqueous de- 

 posits. Such discoveries, on the one hand impress us with 

 the imperfection of the geological record ; on the other, they 

 show us the singular provisions which have been made in the 

 course of geological time for preserving the relics of the ancient 

 world, and which await the industry and skill of collectors to 

 disclose their hidden treasures. 



I may add that I believe all the trees, about thirty in num- 

 ber, which have become exposed in this bed since its dis- 

 covery, have been ransacked for such remains ; and that while 

 the majority 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 scat- 

 tered in every position, and those of different species inter- 

 mingled ; and that being often much more friable than the 

 matrix, much labour is required for their development ; while 

 after all has been done, the result is a congeries of fragments. 

 A few specimens only have been found, showing skeletons 

 complete, or nearly so, and I shall endeavour to figure one or 

 two of these by way of illustration in the present chapter. 



The beds on a level with the top of the reptiliferous erect 

 trees are arenaceous sandstones, with numerous erect Cala- 

 mites. I have searched the surfaces of these beds in vain for 

 bones or footprints of the reptiles which must have traversed 

 them, and which, but for hollow erect trees, would apparently 



