Some Observations on the Eastern Desert of Egypt; with Considerations bearing upon, the Origin of the British Trias

Abstract

I. Introduction. During the past two years I have on several occasions visited that part of the Eastern Desert of Egypt which borders the Red Sea near its junction with the Gulf of Suez. While there I made observations of desert conditions and phenomena which appeared to me to be of interest to the student of the conditions determining the origin of the Triassic rocks of Britain. A few years ago the late J. Lomas dealt very fully with these conditions, having made some studies of South African and Egyptian deserts, and it is with pleasure that I find myself able to confirm or to supplement several of the conclusions to which he came. II. The Igneous ‘Gravels’ and Pebble-Beds. The western side of the Red Sea is flanked by a wall of hills running generally in lines parallel with the general trend of the coast. They rise abruptly from a level or gently sloping coast-plain, which varies in width from under 1 to over 10 miles. The hills are composed chiefly of igneous rocks: red and grey granites, dark andesites and purple porphyries, with some tracts of gneiss and schist. At the foot of the hills, large mounds of angular debris of the igneous rocks occur, running in tongues from the hills out on to the plain, or forming low foot-hills which run parallel with the main range. The mounds themselves consist of unsorted angular blocks and flakes varying greatly in size, and showing as a rule no signs