The area of the Outer Hebrides described in this paper includes North Harris and the Uig, Morsgail and Aline districts in Lewis. In addition, a narrow strip of country is included, north of Loch Erisort and extending eastwards from Balallan as far as the river Laxay on the estate of Soval. North Harris and its adjacent islands such as Scarp and Fladday on the west, and Soay in West Loch Tarbert on the south, forms part of Inverness - shire; Uig, Morsgail and Aline are included in Ross- shire. North Harris, joined to South Harris by the narrow isthmus at Tarbert, is bounded on the south by East and West Loch Tarbert, on the east by Loch Seaforb and on the west by the Atlantic Ocean. Its northern limit is formed partly by Loch Resort and partly by a land boundary much disputed in the past, passing from the head of Loch Resort between Stulaval and Rapaire to Mullach Ruisk and thence to the Amhuin a Mhuil near Aline Lodge on Loch Seaforth. Seaforth Island in Loch Seaforth lies partly in Inverness -shire and partly in Ross -shire. The extensive estate of Uig includes the western part of Lewis west of Little Loch Roag from Loch Resort in the south to the Gallan Head in the north. Morsgail lies between Little Loch Roag and Loch Langavat while Aline includes most of the ground the last-named loch and Loch Seaforth. The area is interesting because of the varied types of scenery which it presents. Thus, North Harris is almost entirely mountainous including six peaks over two thousand feet in height, by far the highest in the Long Island. The hills of the western part of North Harris are continued north into the Uig ! district forming there one of the main areas of high ground in Lewis. North of Harris and east of Uig the hills die away gradually into an undulating moorland with occasional ridges and low isolated hills. This, in turn, passes into the great moor of central Lewis most of which however, lies beyond the area dealt with in this paper. The coast-line is equally varied presenting steep cliffs overlooking dark and narrow sea lochs liké Loch Seaforth and Loch Resort; frowning cliffs front- -ing the open sea as at the Gallan Head, Aird More, Mangersta, or Northwest Scarp; or open stretches of sandy beach fringed with blown sand as at Husinish and Scarp in Harris or the beautiful bay of Uig in Lewis. The physical features, however, will be more fully des - cribed before dealing with the glaciation (p. 76). North Harris, Uig, and Tiorsgail are occupied mainly as deer forests but partly also for grazing. Aline and the moorland near Balallan are devoted to the grazing of sheep and cattle. Cultivated ground which forms a very small proportion of the whole is confined mainly to the open coasts or to the shores of the sea lochs. The population is sparse and confined., in every case to the coast. With the exception of 'few inhabitants at the head of Loch Resort and at Loch Tamanavay the central parts are quite uninhabited and the stranger may walk over the hills for weeks without . meeting a human being. The lack of accommodation and the general inaccessability of the region accounts amply for the lack of attention which has been devoted' in the past to its geology.