A CENTRAL AFRICAN GLACIER OF TRIASSIC AGE 



ing into the mountains. Cross-bedding is common, as are rapid 

 changes from sandstone to shale, probably best to be interpreted 

 by current scouring. The nature of the sediments indicate deep 

 disintegration of the rocks near the shore, while from the fossils 

 Dr. Ulrich is inclined to believe the water to have been at least 

 cool. 



LUBILACHE IN THE ZONE OF THE MANIEMA 



In the Maniema zone in the Lualaba Valley and in the valleys 

 of its tributaries, west of the Eastern Frontier Mountains, the 

 Lubilache covers a large area, as shown in Fig. 2. Within the 

 zone isolated hills and mountain groups of older granites, gneisses, 

 schists, and folded sedimentary rocks rise above the dissected plain 

 of the flat-l3dng series. These older rocks probably stood as islands 

 in the lake in which the Lubilache was deposited. 



The general character of the beds of this series has been described,^ 

 but a more detailed description of the basal beds will be given, as it 

 is at this horizon that evidences of glacial action were noted. 



LUBILACHE BASAL CONGLOMERATE IN THE MANIEMA 



The basal beds are best exposed along the Lualaba River, and 

 the lower Lulindi, and here they have an entirely different char- 

 acter from elsewhere in the Maniema and other districts, as 

 known to the writers. Indeed very coarse conglomerates at 

 the base of these flat-lying sandstones and shales are confined to 

 the immediate valleys of these streams. Elsewhere where the 

 conglomeratic phase occurs the pebbles are rarely over an inch in 

 diameter and sparsely distributed. This is true even where con- 

 glomeratic beds occur around the hills of granites, schists, and other 

 older rocks. 



In the immediate valley of the Lualaba and lower Lulindi 

 rivers, between 3° 30' and 5° south of the equator (our work did 

 not extend south of the 5th parallel) the basal 5 to 20 feet of the 

 Lubilache is an exceedingly coarse conglomerate. This con- 

 glomerate is morainal material, deposited by a tongue of a glacier 

 which followed down the Lualaba Valley probably prior to its 

 becoming a gulf of the great body of water in which the Lubilache 

 was deposited. The morainal matter appears to have been but 

 slightly reworked by the waters of the lake. 



