Geological Society. 457 



Scorpana, a Cheironectes which is figured in Ross's Annual for 1835, 

 a Dajaus closely resembling its American prototypes, several hand- 

 some Balistes and Monacanthi, a Diodon and several Tetrodontes, a 

 new form of Torpedo, some fresh-water fishes, and several other sea 

 ones, are reserved for a future communication. 



GEOLOGICAL SOCIETY. 



Nov. 6, 1839. — A paper was read, " On the relative ages of the 

 tertiary and post-tertiary deposits of the Basin of the Clyde," 

 by James Smith, Esq., of Jordan Hill, F.G.S. 



In former memoirs, Mr. Smith described the indications which he 

 had observed of changes in the relative level of sea and land in the 

 basin of the Clyde, by which deposits had been laid dry during an 

 extremely recent geological epoch * ; and the evidences adduced by 

 the arctic character of several of the shells, that the climate of Scot- 

 land was colder while these beds were accumulating than it is at pre- 

 sentf. In this paper he confines his remarks to the results of sub- 

 sequent observations, which prove, that in these comparative modern 

 deposits there are two distinct formations, differing in climate and 

 the character of their fauna, and separated by a wide interval of time. 

 In the lower or older of these formations, Mr. Smith has found from 

 10 to 15 per cent, of extinct or unknown species, and he accordingly 

 places it in Mr. Lyell's proposed pleistocene system ; whilst in the 

 upper or newer he has found only one species which exists in the 

 present seas, and he accordingly ranges it among the post-tertiary 

 formations of that author. Both these deposits, however, are an- 

 terior to the recent or human period. 



In the lower or pleistocene formation, Mr Smith includes the 

 " till " or unstratified accumulation of clay and boulders, and the 

 overlying beds of sand, gravel, and clay containing a mixture of un- 

 known species of shells. He is of opinion that the beds presenting 

 the same order of superposition in the basins of the Forth and the 

 Tay, including the submarine forest of the latter, will be found to 

 be of the same age, though nothing at present is known of their 

 fossils, except the discovery in the elevated beds of the Tay of the 

 Nucula corbuloides by Mr. Lyell ; and that the parallel roads of 

 Glenroy, recently shown by Mr. Darwin to be of marine origin, may 

 be of cotemporaneous formation. Mr. Smith is also convinced, that 

 a very great proportion of the superficial beds of sand, gravel, and clay 

 are tertiary, although the evidence must sometimes be uncertain, 

 owing to the want of organic remains. 



Proceedings, vol. ii. p. 427. t Ibid. vol. iii. p. 118. See also 



• 



Mr. Smith's paper in the Wernerian Society's Transactions, vol. viii. 



