21 
LAKE-DTVTILLINGS IN THE VALE OF PICKERING. BY J. SPINK. 
{Read 26th April, 1895.) 
The Vale of Pickering, or, as it is sometimes called by geologists, 
Pickering Lake, is an alluvial plain, bounded on the north and west 
by the North York Moors and their off-shoots, and on the south and 
east by the Yorkshire "Wolds. It is about eighteen miles long from 
east to west, and has an average breadth of eight miles. At some 
period it has been a lake, whose waters found an outlet into the sea 
by the valley at Scarborough, and by the Hertford Cut at Filey. It 
is now drained by the Derwent and its tributaries, which escape into 
the Ouse drainage district through a gap between the Wolds and the 
Howardian Hills at Huttons Ambo Station. The southern portion 
is known as the Marishes (Marshes). 
One of the tributaries of the Derwent, on the western side, is 
the Costa, which rises in Keld-Head Spring from a fault of the lime- 
stone meeting the Kimmeridge Clay half a mile to the west of 
Pickering, a good stream of the purest water, and of such volume 
as to work two flour mills within a mile of its source. It flows south- 
west and south for four miles, receives Pickering Beck at Kirby- 
Misperton Bridge, and joins the Rye just above Howe Bridge, three 
miles to the north of Malton. About two hundred years ago the 
present channel was made to confine its waters ; before then it must 
have spread over the land to a considerable distance, as the left bank 
is for the first mile much higher than the adjacent cultivated land. 
This, it may be presumed, was the last remnant of the pre-historic 
lake. 
On several occasions, during the annual process of mowing the 
weeds and clearing the bed of the stream, many bones of animals and 
one human skull have been drawn out. This circumstance led Mr. 
