324 PALEONTOLOGY. 



forming the great arms or inlets ; then, lakes ; and afterwards dry 

 ground ; and that those lakes that now exist were much larger. For 

 we may observe that the rivers that supply those lakes are carrying 

 along whatever can be mixed with them, and with such rapidity as not 

 to allow of a deposit till [they have] arrived at the lake ; while, on the 

 other hand, the water which runs out is clear, because it runs from the 

 surface of the lake." — P. xi. 



Hunter then proceeds to consider the mode of operation of water, 

 by its wearing power when in motion, and by the deposit of matters 

 carried along, and retained for a longer and shorter time in suspension ; 

 as illustrated by the deposits at the mouths of the Scheldt, the Rhine, 

 and the Maese. 



" This must be more remarkable with the Ganges, which runs through 

 an extent of 1500 miles, and shall only descend 20 feet in 60 miles ; 

 the Nile ; the Mississippi, which runs above 2000 miles, and opens by a 

 vast number of rivers, with many of the other vast rivers in America, 

 which become the great deposit of the materials of the river brought 

 from the land above." Speculating upon the results of this aqueous 

 action, he writes : — " The Red Sea will in time be only a flat valley, 

 through which the rivers which empty themselves into it will run, 

 terminating in the sea in one or more mouths, according to the surface 

 at the bottom, which probably may form a country like Holland ; and 

 in all probability the Red Sea and the Mediterranean were one piece of 

 water, which would have made Africa an island ; and it is very probable 

 the Mediterranean will be some day a lake, like the Caspian and the 

 Black Sea."— P. xiv. 



"The mechanical substances being of different kind respecting solidity, 

 are accordingly carried to very different distances. Gravel goes but a 

 little way ; sand a little further ; clay and chalk still further ; and if we 

 were to trace the mould on from an inland country towards the sea, in 

 the course of a river, we might find the following appearances — gravel ; 

 gravel and sand ; sand and clay, forming loam ; or sand and chalk, form- 

 ing marl ; and at last wholly clay, which will be carried more or less 

 some way into the sea." — P. xix. 



" In these deposits of sand and mud are found the bones of large 

 animals, such as elephants, rhinoceroses, buffaloes, &c. ; and indeed 

 these are found along the banks of almost all the rivers in Siberia, 

 scattered here and there, sometimes in greater, sometimes in less 

 numbers. The beds in which they are found are mixed with fish-bones, 

 glossopetrae, wood loaded with ochre. 



" Clay, from being a compressible substance, will be compressed 

 more or less, becoming hard as stone, also forming select masses. It 





