THE GEOLOGY OF PLYMOUTH. 
475 
formations which I have described, and date back to a time when 
the limestone rocks which enclose the fissures were but slightly 
raised above the waters, and when therefore nothing was easier 
than the introduction into the caverns of bodies of animals swept 
down the stream, probably in time of flood ; just as they are com- 
monly swept down the rivers of tropical countries in the present 
day. This view has the double advantage of reconciling difficulties, 
and of agreeing with the generally-observed facts. 
Finally, as to the raised beaches. Mr. Bellamy, in his " Natural 
History," states that the height of the ancient beach on the Hoe 
was generally about thirty feet above high-water mark ; and de- 
scribes a patch as it then existed (1839), twenty feet in depth, 
and fifty feet above high water. It rested on a shelf of smoothened 
rock, which sloped gently seawards, and consisted of regularly 
" superposed or stratified' 1 layers, varying from extremely fine 
sand to moderately-sized pebbles. As traces of pholades were 
discovered in the rock on which these deposits rested, there can, I 
think, be no doubt that they were what they were taken to be — a 
raised beach. 
I may add that pholas borings are said to occur in the limestone 
of Hooe, nearly 100 feet above the present tide level; but that 
doubt has been cast upon their origin. 
This brings our narrative of the geological history of Plymouth 
down to (geologically) recent times ; and here, then, I close the 
record. 
SOME EEMAEKS ON EECENT SPECULATIONS ON 
THE OEIGIN AND SPECIFIC CHAEACTEE 
OF MAN. 
ABSTRACT OF EEV. J. ER SEINE RISK'S PAPER. 
(Read December 9th, 1875. ) 
Darwin's theory of the origin of man stated. Arguments in 
support of his conclusion that " man is descended from a hairy 
quadruped, furnished with a tail and pointed ears, probably arbo- 
real in its habits, and an inhabitant of the old world." Argument 
