THE GLACIAL GEOLOGY OF NIDDERDALE

Abstract

Introduction. The catchment basin of the River Nidd, from its source on Great Whernside to its termination at Nun Monkton, approximately forty-five miles in length and covering an area of about 450 square miles, presents interesting features of superficial geology which will be considered in some detail. The valley is completely separated from the adjoining dales of the Cover, Ure, and Wharfe in its upper reaches by high peat-covered moorland, attaining a height of 2,310 feet O.D. The solid geology of the area is largely dependent on the Pennine Anticline so that sandstones and shales of the Millstone Grit Series outcrop in Upper Nidderdale; Magnesian Limestone near Knaresborough; and Keuper and Bunter Sandstones of Triassic age east of Cowthorpe. Yoredale limestones and shales occur in the valley bottom: ( a ) from Angram to Scar House; ( b ) near Manchester and Goyden, pot-holes below Lofthouse Moor; and ( c ) at the junction of the Nidd and How Stean Beck near Lofthouse village. Lower Carboniferous rocks again outcrop near Harrogate, due to a subsidiary anticline. South of Ripley there is an outlier of Permian Magnesian Limestone. A lithologically interesting outcrop is a particular band of blue chert, occurring in situ above Angram just below 1,200 feet O.D. in the Yoredale beds. No igneous or metamorphic rocks are known to occur in Nidderdale. Previous workers on the glacial geology of the area are Professor H. Carvill Lewis,1 Professor P. F. Kendall,2 and others who will be noted in due course. Evidences of Glaciation. I. Drift.—The ...