THE GEOLOGICAL MIDDLE AGE. 155 
tlu; course of time. When Cuvier first saw the 
teeth of a Wealden Reptile, he pronounced them 
to be those of a Rhinoceros, so mammalian were 
they in their appearance. So, when Sommering 
first saw the remains of a Jurassic Pterodactyl, 
he pronounced them to be those of a Bird. These 
mistakes were not due to a superficial judgment 
in men who knew Nature so well, but to this pro- 
phetic character in the early types themselves, in 
which features were united never known to exist 
together in our days, and presenting a kind of 
combination wholly new to scientific men at that 
* ime. 
The Jurassic epoch, next in succession, was a 
very important one in the history of Europe. It 
completed the junction of several of the larger 
islands, filling the channel between the central 
plateau of France and the Belgian island, as well 
as that between the former and the island of Bre- 
tagne, so that France was now a sort of crescent 
of land holding a Jurassic sea in its centre, Bre- 
tagne and Belgium forming the two horns. This 
Jurassic basin or inland sea united England and 
France, and it may not be amiss to say a word 
here of its subsequent transformations. During 
the long succession of Jurassic periods, the depos- 
its of that epoch, chiefly limestone and clays, with 
liere and there a bed of sand, were accumulated 
