GLACIAL SUCCESSION IN" EUROPE. 149 



colder than those that followed. Now we find that the epoch of maximum glaciation 

 supervened in early Pleistocene times, and that three separate and distinct glacial epochs 

 of diminished severity followed. Of these three, the first would appear to have been 

 almost as severe as that which preceded it, and it certainly much surpassed in severity 

 the cold epochs of the later stages. But the epoch of maximum glaciation, or the first of 

 the Pleistocene series, was not the earliest glacial epoch. It seems to have been pre- 

 ceded by one of somewhat less severity than itself, but which nevertheless, as we gather 

 from the observations of Pence and his collaborateurs, was about as important as that 

 which came after the epoch of maximum glaciation. Hence it would appear that the 

 correspondence of the geological evidence with the requirements of the astronomical 

 theory is as close as we could expect it to be. Four glacial with intervening genial 

 epochs appear to have fallen within Pleistocene times ; while towards the close of the 

 Pliocene, or at the beginning of the Pleistocene Period, according as we choose to classify 

 the deposits, an earlier glacial epoch, followed by genial interglacial conditions, super- 

 vened. 



In this outline of a large subject it has not been possible to do mor,e than indicate 

 very briefly the general nature of the evidence upon which the chief conclusions are 

 based. I hope, however, to have an opportunity ere long of dealing with the whole 

 question in detail. 



EXPLANATION OF PLATE. 



Map of Europe showing the areas occupied by ice during the Epoch of Maximum Glaciation (Second 

 Glacial Epoch), and the extent of glaciation in Scandinavia, Finland, Baltic coast-lands, &c, and the British 

 Islands during the Fourth Glacial Epoch. For the limits of the greater glaciation on the Continent, 

 Habenicht, Penck, Nikitin, and Nathorst have been followed. The Great Baltic Glacier is chiefly after 

 De Geer. 



