1891.] BRITISH CENTRAL AFRICA. 311 



The fullest and most interesting account of the Geology of the 

 Nyassa country is that given hy Prof. Henry Drummoud as " a 

 Geological Sketch" in chapter viii. of his 'Tropical Africa,' pubHshed 

 in 1881. This sketch embraces the whole of the country he traversed 

 from the mouth of the Zambesi to the Tanganyika Plateau. A 

 coloured map accompanying this sketch serves to indicate in a 

 general way the positions of the rocks that have been recorded by 

 others, or directly observed by Prof. Drummond himself. In this 

 chapter the fossil Fishes found by the author are described in detail 

 by Dr. R. H. Traqnair. 



Quite recently Prof. Rupert Jones (Geol. Map;., Dec. 1890) has 

 given an account of the coal and the fossil shells which have been 

 found near the N.W. extremity of Lake Nyassa. 



StHrting from the mouth of the Zambesi, at a distance of about 

 50 miles from the coast, there is, according to Prof. Drummond, an 

 ancient Coral-reef, which, although standing only a few feet above 

 the sea-level, probably indicates a slight elevation of this part of the 



COilst. 



About 20 miles further inland near Shupanga, and still only at a 

 very slight elevation, sedimentary rocks were met with consisting of 

 " a few thin beds of red and yellow sandstones and fine conglomer- 

 ates." No fossils were found ; but these deposits are believed to he 

 of the same age as the beds at the Cape, which are known as the 

 Karoo formation (Lowest Mesozoic), which seems to extend as far 

 north as Zanzibar and Mombasa. 



Beds of coal are said to occur far up the Zambesi, at a place 

 called Tete, and are probably associated with beds of the Karoo age, 

 which it is thought will be found to form a narrow belt fringing the 

 plateau of the interior. 



A little above the junction of the Shire River and the Zambesi, 

 the first hills of the plateau begin ; they vary in height from 100 

 or 200 feet to 2000 feet, and those examined by Prof. Drummond 

 " consisted entirely of white quartzite," the only quartzite he saw in 

 Central Africa. At the foot of one of these hills (Morumballa) there 

 is a hot spring, described by Livingstone. 



Livingstone spoke of coal occurring about 2 or 3 days' journey 

 N.W. of Morumballa, but Prof. Drummond, after careful search, 

 could find no trace of coal in the neighbourhood, and is of opinion 

 that a black rock (very dark diorite) which does occur, and in the 

 distance looks very like coal, m.ust have misled Livingstone. 



The great African Plateau, including the upper part of the Shire 

 River and the greater part of the country surrounding the Nyassa 

 Lake, as well as half the plateau between the Nyassa and the Tan- 

 ganyika, consists almost wholly oi granite and gneiss; the character 

 of the rocks being remarkably uniform throughout the area. 



Volcanic rocks occur at several places along the Zambesi and also 

 at the northern end of the Nyassa. 



About six miles S. by E. of Mount Waller, on the N.W. shore of 

 Lake Nyassa, Mr. James Stewart noticed some coal occurring about 

 a mile and a half from the Lake shore and about 500 feet above its 



