NOTE ON CLAY WITH SAND BALLS AT HUNMANBY

TRANSACTIONS OF THE HULL GEOLOGICAL SOCIETY

Volume 7, page 115-7

NOTE ON CLAY WITH SAND BALLS AT HUNMANBY.

SIDNEY MELMORE, B.Sc., F.G.S.

In his paper "On the Divisions of the Glacial Beds in Filey Bay," [Proc. Yorks. Geol. Soc., Vol., VII 1879, p. 167. ] G. W. Lamplugh described a broad deep hollow in the Purple Boulder Clay " between Reighton and Hunmanby, which has not only been scooped out, but has also been completely filled in again with finely laminated sands and warps, in places nearly 4° feet thick, almost free from pebbles, save a few coal specks."

Owing to a recent fall of cliff these deposits are at present excellently exposed at a place on the shore a short distance south of the point where the road from Moor House, Hunmanby, runs down to the beach. [The section was noticed by Dr. John S, Gayner and the present writer on 22nd February, 1934]

The clear section is at the foot of the cliff and is about 12 or 15 feet long and 10 feet high. At the base there is pale chocolate-coloured laminated loam. Above, and resting on a level surface, is a bed 4½ feet thick which can best be described as consisting .of cobbles made of sand embedded in a gutta-percha clay. These balls, which are about 6 inches in diameter, consist of very fine-grained pale yellow sand with so little coherence that they readily disintegrate in the fingers, and in consequence weather with the greatest ease, leaving concave impressions in the clay. Their matrix is in marked contrast, being the most tenaceous kind of dark chocolate-coloured clay. Overlying the ball bed there is more laminated loam similar to that underlying it. Above this the section is obscured by slips.

These objects leave one with the impression that they were fragments of a sandstone (sand cemented by ice) which, after being transported into their present position, remained frozen long enough for the gutta-percha clay to accumulate in the interstices.

A short distance south of this section a true laminated clay takes the place of the lower laminated loam. It is there seen there seen resting on the Purple Boulder Clay with a well-marked dip landward. The ball-bed is not mentioned by Lamplugh and has evidently never been exposed to view till now.