222 Proceedings of Learned Societies. 



excellent negative photograph of a bust by Chantrey was taken by 

 Mr. Brothers. 



The photographs produced by magnesium light are of a very 

 agreeable character ; and as the amount of metal required is very 

 small, the process is not expensive, and it is probable that it may 

 come into general use. 



GEOLOGICAL SOCIETY OF LONDOK-J^J. 19. 



Succession of British Mesozoic Strata. — The President in 

 his anniversary address discussed the breaks in the succession of the 

 British Mesozoic Strata. First, he examined the numerical relations 

 which different classes bore to one another in Palaeozoic times, 

 comparing them with their development in secondary epochs. The 

 general conclusion arrived at was that a long interval of time, oftem 

 stratigraphically unrepresented, is an invariable accompaniment of 

 a break in the succession of species ; and the more special inference 

 was that, in cases of superposition, in proportion as the species are 

 more or less continuous, that is to say, as the break in life is partial 

 or complete, first in the species, but more importantly in the loss of 

 old and the appearance of new genera, so was the interval of time 

 shorter or longer that elapsed between the close of the lower and 

 the commencement of the upper formation. 



Feb. 24. 



Recent Discoveries of Flint Implements in Drift Deposits 

 in Hants and Wilts. — Flint implements having recently been 

 found on the sea-shore, about midway between Southampton and 

 Gosport, and also at Fisherton near Salisbury, Mr. J. Evans visited 

 these localities in company with Mr. Prestwich, and gave the results 

 of his observations. 



After describing the implements from near Southampton, and 

 having shown that their condition is identical with that of the 

 materials composing the gravel capping the adjacent cliff, Mr. 

 Evans maintained the great antiquity of these remains, as proved 

 by the circumstance that the gravel-beds, like those of Reculver, 

 are of fiuviatile origin, although now abutting on the sea. 



Mr. Evans then described the Fisherton implements, and the 

 gravel-pits from which they were obtained. The relation of the 

 high-level gravels (in which the implements were found) to the 

 lower-level gravels of the Valley of the Avon was discussed, and the 

 geological features of the former deposits particularly described; lists 

 of the fossils (including the mammalia and the land and freshwater 

 shells) being also given. Jlr. Evans came to the conclusion that 

 the fossils bore evidence of the climate, at the time when they were 

 deposited, having been more rigorous, at any rate in the winter, 

 than it now is ; and to this cause he attributed the comparatively 

 greater excavating power of the early Post-pliocene rivers. 



March 9. 

 On tiif. Discovery of tiik Scales of Pteraspis. — Mr. E. K. 

 Lankester communicated a paper on the Pteraspis, in which the sue- 



