During the period 1913–16, I conducted a Survey of the Agricultural Zoology of the Aberystwyth Area, for which purpose the University authorities received a grant from the Board of Agriculture. The area thus examined comprised N. Cardiganshire and some adjacent borders of Montgomeryshire, roughly about 250 sq. miles. It falls into three main physical divisions:

I. The mountainous upland (or high plateau) of solid rocks frequently covered by a considerable depth of peat. The rock succession is only irregularly exposed in deep stream cuttings, while these valleys are occupied by boulder clay and river deposits.

II. The surface of the coastal plateau shows exposures of rock and of boulder clay. The clay is usually exposed and rarely covered with peat.

III. The fall line, which is intermediate. Here the boulder clay generally follows the valleys, and it is usually covered with a thin layer of peat. Much of this is readily cut through by small streams.