442 SCIENCE PROGRESS. 



them numerous tropical plants and animals. Cases have 

 been recorded in which even jaguars and other large 

 mammals have been carried down to the lower reaches of 

 the Parana and the region of its delta." 



Other conditions, which recall Fayol's description of the 

 Commentrv Permo-Carboniferous lake basins and the water- 

 borne vegetable sediment, have been described to me by 

 Mr. Philip Lake, late of the Indian Geological Survey. On 

 the floor of the Travancore back waters of Southern India, 

 a very carbonaceous deposit is being formed from the 

 material carried to the sea by rivers which have flowed 

 through a forest-covered country ; these extensive beds of 

 fairly pure vegetable sediment, in process of accumulation, 

 may well be compared with the first stages in the building 

 up of coal seams. Dr. Gregory, in a paper on the Norfolk 

 Broads, would have us look nearer home for a modern 

 illustration of coal-forming conditions. He suggests that 

 a study of the Broads " enables us to follow in detail the 

 history of a great estuary, and it presents us with, perhaps, 

 the closest analogy to the conditions of the formation of our 

 coalfields ". 



We may sum up the whole matter by expressing the 

 conviction that the weight of evidence seems to tip the 

 balance of opinion very materially towards the theory of 

 drifting, and subaqueous sedimentation, for the majority of 

 the Palaeozoic coal seams. Some coals are probably old 

 peat bogs or similar autochthonous formations, which have 

 passed into the state of coal as the result of favourable 

 physical conditions. But while suggesting the allochthonous 

 manner of formation as the most widely applicable, we may 

 conclude with the saving clause that "die Natur nicht alles 

 liber einen Leist geschlagen hat". 1 



BIBLIOGRAPHY. 



Balfour, J. H. On certain vegetable organisms found in coal 

 from Fordel. Trans. R. Sac, Edin., vol. xxi., 1857, p. 187. 



1 Giimbel, p. 206. 



