132 Canadian Record of Science. 



The picture presented by the wide swamps and dark 

 ponds and sluggish streams of the coal-formation period, 

 with the creatures of low organization by which they were 

 inhabited, is not an attractive one ; but these conditions, 

 which spread so widely over our continents in the carbon- 

 iferous period, were those suitable to the accumulation of 

 the great deposits of coal so essential to us in the present 

 condition of the world. The animals which form the sub- 

 ject of the present paper, though of little value or interest 

 in themselves, give much information as to the conditions 

 of accumulation of coal, and it is a source of gratification to 

 the writer of this paper to find that as interpreted by their 

 latest investigator, Dr. Wheelton Hind, they tend to estab- 

 lish more firmly the conclusions as to the manner of the 

 production of coal-beds for which he has contended for so 

 many years, and which are so well illustrated by the 

 admirable sections of the coal-bearing rocks seen in the 

 coast-cliffs of Nova Scotia and Cape Breton. 



Throughout the thousands of feet of such rocks, con- 

 stituting the productive coal-measures as exposed in these 

 sections, I have shown ] that there is an entire absence of 

 properly marine or oceanic remains ; and the accumulations 

 of sediment and organic matter, and the animal and vege- 

 table fossils so abundantly present, all point to the existence 

 of wide swampy flats, traversed by ditch like creeks, and 

 with shallow lakes or lagoons, supporting an exuberant 

 plant-life, and from time to time inundated. In this 

 way the beds of coal, underlaid as they are by underclays 

 with roots, and overlaid by clays and sands containing pros- 

 trate and drift plants, and associated with beds holding a 

 fauna appropriate to such conditions, were accumulated 

 by growth in situ in the manner of modern bogs The 

 accumulation of successive beds with intervening shales and 

 sandstones, is due to the gradual or intermittent subsidence 

 of the areas of deposition under the weight of the sedi- 

 ments laid down upon them, as we see at the present day 

 in the deltas of great rivers. 



1 Acadian geology, chap. XI. 



