1878.] 
The British Association. 
533 
each underlying boulder clays of different ages and some- 
what different characters, the Hessle, the purple, and chalky 
boulder clay. This raises two main questions ; first, as to 
how far Dr. Croll’s theory of the great alternations of climate 
during the glacial period can be safely maintained ; and 
secondly, how far the observations as to the discovery of 
implements in the so-called Brandon beds underlying the 
chalky boulder clay can be substantiated. Another question 
is how far the palaeolithic deposits can be divided into those 
of modern and ancient valleys, separated from each other 
by the purple boulder clay, and the later of the two older 
than the Hessle beds. He would only observe, that in a 
considerable number of cases the gravels containing the 
implements can be distinctly shown to be of much later 
date than the chalky boulder clay, and that if the imple- 
ments occur in successive beds in the same district, each 
separated from the other by an enormous lapse of time, 
during which the whole country was buried beneath in- 
credibly large masses of invading ice, and the whole mam- 
malian fauna was driven away, it was a very remarkable 
circumstance. It was not the less refnarkable because this 
succession of different palaeolithic ages seemed to be observ- 
able in one small district only, and there was as close a 
resemblance between the instruments of the presumedly 
different ages as there was between those of admittedly the 
same date. He had always maintained the probability of 
evidence being found of the existence of man at an earlier 
period than that of the post-glacial or quaternary river 
gravels, but, as in all other cases, it appeared to him desir- 
able that the evidence brought forward should be thoroughly 
sifted and all probability of misapprehension removed before 
it was finally accepted. In the present state of our know- 
ledge, he did not feel confident that the evidence as to these 
three successive palaeolithic deposits had arrived at this 
satisfactory stage. At the same time it must be borne in 
mind that if we make the palaeolithic period to embrace npt 
only the river gravels but the cave deposits of which the 
south of France furnishes such typical examples, its dura- 
tion must have been of vast extent. 
In connection with the question of glacial and inter-glacial pe- 
riods, Dr.Evansmentionedthatof climatal changes ingeneral. 
The return of the ArCtic Expedition, and the reports of the 
geological observations made during its progress, which have 
been published by Captain Fielden, one of the naturalists 
to the expedition, in conjunction with Mr. De Ranee and 
Professor Heer, have conferred additional interest on the 
