Correspondence — Professor W. Boyd Dawlnns. 285- 



In tlie whole of this region, the only post-Primary rocks met 

 with, other than those of comparatively modern alluvial origin, were 

 chocolate-coloured shales (Buta Shales) and sandstone, and an oolitic 

 limestone, on the extreme west. 



From the Lipodongu Falls on the Eubi, and thence through Poko 

 to Rungu, on the Bomokandi Eiver, none but granitic rocks (gneisses) 

 were observed. Along the Uelle, from Bima to Bomokandi, the same 

 rocks were seen. 



In the centre of the region mica-schists, quartzites, and similar 

 metamorphic rocks replace the granite wholly or in part. A notice- 

 able feature here is the presence of a range of isolated hills, com- 

 posed almost completely of great beds of magnetite and hematite 

 occurring in the schistose series. 



In the south-eastern portion of the region visited, between the 

 Uelle-Kimbali and Bomokandi Eivers, a great plutonic massif is laid 

 bare in the mountainous district of Arebi. 



From the presence of iron-ore and schists at Mount Tena on the 

 south-west and analogous rocks at Mount Gaima on the north-west 

 side of the massif, and from the fact that the dip is in each case 

 strongly away from the intervening country, it is suggested that 

 these rocks have been uplifted and tilted by the plutonic complex, 

 and that the beds of Mount Tena and Mount Ga'ima are identical 

 in age. 



The plutonic massif itself contains microclinic gneiss and 

 abundant diabasic rocks, and the same rocks in all stages « of 

 dynamo-metamorphism. 



On the boundary between the Congo State and the Bahr-el-Ghazel, 

 several hills made up of rocks of coarse gneissose and schistose 

 character are described ; some of these rocks are rich in tourmaline, 

 kj'anite, and garnet in large crystals. 



From the region of the Enclave de Lado and the western side of 

 the Nile between Lado and Dufile, mica-schists, quartzites, and 

 microcline-gneisses are described. 



The alluvium of a large part of the Uelle is covered, on the 

 higher ground, by a deposit of limonitic conglomerate; in places 

 this may be due to the decomposition in sit'u of the alluvium, but 

 in the neighbourhood of the iron mountains a sort of passage may 

 be seen between a conglomerate of fresh iron-ores and the more 

 general type of limonitic conglomerate (laterite ?). 



THE DISCOVERY OF THE SOUTH-EASTEEN COALFIELD. 



Sir,— In the last edition of "The Coalfields of Great Britain" 

 Professor Hull gives an account of the discovery of the above 

 coalfield which cannot, in the interests of fairness and truth, be 

 allowed to pass current without correction. 



" The credit," he writes (p. 282), "of experimentally demonstrating, 

 the existence of coal-seams below the Chalk is due to Mr. Francis 



