IX.—Geological Sketch of the North-western Extremity of Sussex, and the adjoining Parts of Hants and Surrey.

Abstract

I propose to illustrate in this memoir the order of superposition of the strata in that north-western part of Sussex which is bounded on the south by the chalk escarpment of the South-downs, and in those adjoining parts of Hampshire and Surrey which are bounded severally, on the west by the Alton chalk-hills, and on the north by the North-downs. Having examined a portion of this country with my friend Dr. Fitton, I was encouraged by him to attempt an exact delineation of the whole, by colouring the Ordnance map according to geological formations *. This task being now accomplished, I beg to lay the result before the Geological Society, together with such illustrative specimens of the strata and their fossils as I have been able to collect in the course of last summer. The formations of which this district is composed, begin to emerge from the superior strata at the northern extremity of the parish of Bentley in Hants, 6 miles north-east of Alton; and they range from thence to the south and east, until their escarpments are cut through by the Arun, which river I have chosen to make the limit of my present observations. The chalk escarpments of the Alton hills and of the South-downs, converging towards Petersfield, are united at an acute angle in the parish of East Meon, 4 miles west of the former place; and within that angle the inferior strata are disposed conformably. Hence by assuming the Weald clay in the little valley