Lake Bosumtwi, Ashanti

LAKE BOSUMTWI lies about 20 miles south-east of Kumasi, in lat. 6? 30' N. and long. i? 25' W. Lakes are rare topographical phenomena in tropical West Africa. None other than Bosumtwi is known in the Gold Coast Colony. The nearest are the Timbuktu lakes (Debo and Faquibine), 700 miles to the north, a small lake (Iyede), 500 miles to the east in Southern Nigeria, and Lake Chad, 1050 miles away to the north-east. All these latter, and a few others of trifling size, are merely phases of development of the Niger or of the Shari river-beds. Unlike them however Bosumtwi does not lie in the channel, present or ancient, of any river; it is not only situated high up on the watershed between the Anum and the Adra branch of the Ofin, the Anum and the Ofin being the two main tributaries of the Prah River, but its waters are also selfcontained and are wholly isolated from the general drainage system of southern Ashanti. The general altitude ofthe feebly dissected upland in which Bosumtwi lies is about 950 feet above sea-level. This upland extends far to the north and to the south, and its general level is broken only by the 3 mile wide north-east to south-west striking Obuom Range, of an average height of 1600 feet above sea-level, and with two peaks reaching heights of 1775 feet and 2225 feet respectively. Both upland and range are densely forest clad. The Obuom Range forms part of the great "gold belt" of the Gold Coast Colony, and, 30 miles to the south-west, it contains the famous Obuasi gold mine of the Ashanti Goldfields Corporation. Lake Bosumtwi is roughly circular, with an average diameter ofa little under 5 miles. It lies at the l^ottom of a great crater with its surface waters 900 to 1200 feet below the crater rim. The diameter of the crater at the rim is about