AIR-BREATHERS OF THE COAL PERIOD. 6 



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 1862,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. 



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. 



II. Footprints. 



Plate I.t 



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 



* 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. 



t This plate will be given in the next number. 



