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of species in order to understand what bearing these 
phenomena have on the theory of Natural Selection ; 
and, in dealing with these subjects, I shall be compelled 
to refer to the difficulties which we have seen to stand 
in the way of the theory of Natural Selection. 
Ample evidence has been adduced to show that some 
species have remained practically unaltered through cen 
turies of historical ages and through aeons of geological 
time. Cuvier compared the mummied remains of certain 
animals in Egypt with organisms of the same species 
still living in that country, and came to the conclusion 
that no appreciable change had taken place for 3000 or 
4000 years. Shells are found in the superficial deposits 
which cover the rocky subsoil of Goat Island, near the 
Falls of Niagara, belonging to exactly the same species 
as those which now inhabit the still waters of Lake Erie ; 
and it has been thence inferred that the species has re 
mained unaltered for 30,000 years. As we work our way 
through the great series of the tertiary formations, we 
find species identical with those which live in the present 
day. The lamp shells (Terebratula) of the cretaceous 
epoch exist unchanged or with insignificant variations to 
the present day. The very substance of our English chalk 
consists of skeletons of Globigerince which are identical 
with the Globigerince of to-day. 
“ Among the higher animals, some types have had a marvellous 
duration. In the chalk, for example, there is found a fish belonging 
to the highest and the most differentiated group of osseous fishes, 
which goes by the name of Beryx. The remains of that fish are 
among the most beautiful and well-preserved of the fossils found in 
our English chalk. It can be studied anatomically, so far as the 
hard parts are concerned, almost as well as if it were a recent fish. 
But the genus Beryx is represented, at the present day, by very 
closely-allied species which are living in the Pacific and Atlantic 
Oceans. . . . The carboniferous formations, in Europe and in 
America, contain the remains of scorpions in an admirable state