154 DAVIS : SOURCE OF BOULDERS IN C ALDER VALLEY. 
can be no reason why the ice-floes should not have been 
occasionally stranded on some of the higher lands below the 
level of the water, and there have left evidence of their 
presence in heaps of travelled boulders, as well as in the 
lower parts of the valley. But such evidence is entirely 
wanting. 
On the other hand, the glacial clays are extended across 
the mouth of the Calder, and the boulders derived from them 
may have been washed into the valley, during a slight 
submergence, by the action of the tides and waves, and also 
borne up the valley by ice-floes. The statement of Prof. 
Green that a glacier at one time extended as far south as 
Barnsley, and left its detritus spread over the country 
northwards, furnishes a source for the boulders actually 
within the valley of the CaJder as far west as Wakefield, 
and during the denudation of this district by marine action 
the boulders would be naturally washed into the sheltered 
bay which the valley under those circumstances would form. 
It is not necessary that the land should be submerged more 
than 250 or 300 feet ; but if it was lowered to the extent of 
about 350 feet, there is evidence of its former presence in 
the beds of sand and gravel which are found in many places 
on the hill-sides at a nearly uniform height above the sea- 
level. 
THE TRIAS OF THE SOUTHERN PART OF THE VALE OF YORK. 
BY H. FRANKLIN PARSONS, M.D., F.G.S. 
In a paper which I had the honour to read before this 
Society in 1877, on the Alluvial Strata of the lower Ouse 
valley, I described briefly the Triassic rocks upon which 
the newer beds rest ; but, as some further details con- 
cerning them have since come to my knowledge, I have 
thought it proper to bring them before the Society, so that if 
thought fit, they may be embodied in the Proceedings. This 
