THE 



CANADIAN 



NATURALIST AND GEOLOGIST. 



Vol. VIII. FEBRUARY, 1863. No. 1. 



Art. I. — The Air- Breathers, of the Coal Period in Nova Scotia 

 by J. W. Dawson, LL.D., F.R. S., &c. 



I. Introductory. 



The animal population of the earth during the older or palaeo- 

 zoic period of its geological history, is known to us chiefly throuo-h 

 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 plant-bearing Upper 

 Devonian beds of that locality.* It is true also that reptiles of 

 high organization have been found in beds referred to the Upper. 

 Devonian, at Elgin, in Scotland ; but 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. 



* In a letter to the author. It is to be hoped that descriptions of these 

 interesting remains may soon be published. 



Can. Nil. 1 Vol. VIII. 



