The following sites were discovered by Mr. and Mrs. Harry Milton and myself during the summer and autumn of 1926, while I was excavating the Devil's Tower Cave at Gibraltar.

(i) Llanos de la Horadada. This is a surface site, lying on rising ground to the west of the road from San Roque to the Rio Guadiaro, near the seventh kilometre-stone out of San Roque. The Llanos de la Horadada is a group of low hills forming a southern extension of the Sierra del Arco; it takes its name from a tunnel-like cave, the Cueva de la Horadada, which runs through an outcrop of Eocene sandstone about 1 km. to the west of the road.

In a recently-ploughed field lying immediately above the road we found a small number of flint and quartzite implements, two of which, a small disc and a chopper, were unmistakably Mousterian (Fig. II, Nos. 1 and 2). The implements and flakes were all slightly abraded, and those which were made of flint were deeply patinated, some being white and others light brown.