1850.] over the Northern Hemisphere. 307 



and carses corresponds very closely with that of the most recent of our 

 upheavals, of which I have no doubt they form a part. 



I now come to the proofs of a descent having occurred anterior to 

 the upheaval. It is, I think, nearly twenty years since Dr. Fleming 

 described the occurrence of beds of peat, with tree-roots, obviously in 

 situ,* both in the estuary of the Tay and the Bay of Lago. 



The fangs and fibres of the roots are still entire, and as fast in the 

 ground as when alive : the stumps protrude some distance, through 

 the peat bed. Dr. Fleming seems at this time to have supposed that 

 they were confined to the bed of the river ; he does not seem to have 

 been aware that the peat bed was found everywhere under the clay of 

 the low carse, surmounted by from twenty to thirty feet of alluvium. 

 Peat beds of a similar nature are found covered over with a deep layer 

 of alluvium in the valley of the carse, and at Perth. Similar deposits 

 occur at Mount's Bay in Cornwall, in Lincolnshire, and in Orkney. 

 In 1837, in a report drawn up for the Highland Society, on the Geology 

 of the South Eastern portion of Perthshire, I specially adverted to the 

 circumstance of the occurrence of the beds of cockle shells under the 

 silt, and above the peat and tree roots, which seemed to me only capa- 

 ble of being explained on the hypothesis that when the trees grew in 

 the position now occupied by their roots, the surface of the land must 

 have been at least ten feet higher than at present, so as to have placed 

 them above the tide: — that a subsidence of at least twenty feet must 

 have occurred, and that during this period the cockle bed came into 

 existence ; and, as the earth continued to descend, became buried in 

 the mud which now covers it to the depth of ten feet : — that the move- 

 ment must have next changed its direction, raising the cockle bed at 

 least ten feet above its original position, bringing the Carse of Gourie 

 sixteen or twenty feet above the sea, and elevating the tree roots to low 

 water mark. 



The phenomena around us at Bombay exactly correspond with those 

 of the Carse of Gourie. The whole of our littoral formations consist 

 of the concretes already referred to, or of loose sand and shells. From 

 three to ten feet under this (the depth varies) is a bed of blue clay, 



* The books at our command in India are few in number. I am unable to lay 

 my hands on Dr. Fleming's papers: I quote from Dr. Anderson's account of the 

 Geology of Fife, given in Swan's Review of Fife, Vol. I. page 215. 



