ON AN ANCIENT SEA-BEACir. 337 



the Yorkshire Gaol, and P. Society on these beds, he suggested that they 

 might be called Fre-Glacial, since tbey were so distinctly older than the 

 Basement clay, which has been regarded (perhaps witbout much evi- 

 dence) as the oldest bed of the Yorkshire Glacial deposits. But it has 

 since been suggested that the term Sub-Glacial would better indicate 

 this relationsbip without inference as to the age, and our recent dis- 

 covery of foreign pebbles in greater numbers and of larger size than 

 before shows the wisdom of this suggestion. 



While the presence of a few travelled pebbles is scarcely alone suf- 

 ficient evidence of the Glacial age of the beds, since such pebbles occur 

 in beds that are allowed to be Pre-Glacial ; as, for example, in the Norfolk 

 Forest-bed series; yet the fauna, as at present determined, lends no coun- 

 tenance to the view that the beds are actually Pre-Glacial, though, on 

 the other hand, it contains nothing that is decisively against this view. 

 A large number of the bones obtained, however, are yet in an indeter- 

 minable condition, and we hope that when they shall have been repaired 

 and examined they may yield closer results. 



The Basement clay contains so much evidence of the destruction of an 

 old sea-bottom at some distance from the shore, that the idea naturally 

 arises that the beach we have been examining may have formed the shore- 

 line of that period. But the evidence of their respective faunas is quite 

 opposed to this, for the Bridlington shells denote a very cold climate — 

 not quite but nearly the coldest -we have evidence for in Great Britain — 

 whereas the old beach, with its hippopotamus and oysters and its un- 

 frosted cliff- face, indicates a climate, if anything, warmer than we enjoy 

 at present. 



Of course it maybe urged that, as the shell-beds of the Basement clay 

 are not in place, they may have been carried for long distances, and are 

 not evidence for an extreme climate in their present resting-place. But 

 even if far transported they must still have been formed somewhere 

 within the North Sea basin, and the presence of such a fauna anywhere 

 within so shallow and limited an area seems hardly compatible with 

 the contemporaneous occurrence of a warm climate on its shores. So that 

 the correlation of the old beach with the shell-beds of the Basement clay 

 seems an improbable one. 



The presence of foreign pebbles in the beach is certainly evidence for 

 the existence of ice in some form, either during the formation of the beach 

 or prior to it ; but unfortunately we cannot say whether these have been 

 derived from pre-existing Glacial beds somewhere within reach of the 

 sea, or have come more directly through the stranding of small drifting 

 bergs or coast-ice. 



Independently of its fauna, the Basement clay is in itself the proof 

 of a very severe climate, and shows a set of conditions that could not 

 suddenly have arisen. Possibly the minor oscillations that may have 

 occurred during the gradual approach of the great Glacial period, before 

 the maximum cold set in, may account for the somewhat contradictory 

 evidence of these beds. 



It is unfortunate that we have been able to recover so small a portion 

 of the fauna which must have existed at that time. Our list is evidently 

 a mere fragment, and both on land and sea there has undoubtedly been 

 abundant and varied life. 



But the circumstances are not favourable. For sea-shells wo have 

 had only the highest and roughest portion of an old beach to explore, 



1888. 2 



