534 STEVENSOX— THE FORMATION OF COAL BEDS. [Nov. i, 



1. River mud, like the Nile mud of Egypt, containing calcareo- 

 argillaceous concretions. 



2. Friable, fine and coarse conglomerate of quartz grains and 

 pebbles, cemented by ancient mud. 



3. Ancient Nile mud, indurated, with embedded iron-shot clay, 

 silicious limestone and, in the ferruginous portions, marly con- 

 cretions. 



4. Fine and coarse conglomerate, cemented by ancient Nile mud 

 and calcareo-argillaceous matter. It is very hard. 



5. Dark gray freshwater limestone. 



The beds are horizontal and 30 to 36 feet deep. Vegetable 

 remains occur throughout, except in the uppermost bed; the whole 

 is of freshwater origin, the fauna consisting of species now living 

 in the Nile, accompanied by some land forms. These deposits are 

 in the region of widespread floods, w^hose great areal extent is due 

 to vegetation in the river channel, which the river cannot tear out. 

 The type of deposit is different below the first cataract. Newbold^-'^ 

 says that at Thebes one can recognize mica spangles from granite 

 of the first cataract, but at Asfet in the Delta, the spangles are so 

 minute that they can hardly be recognized even with aid of a lens. 

 Pebbles are very rare in the delta area; but the composition and 

 texture of the deposit vary according to position, coarse material 

 being confined to the main channels and their borders ; fine material 

 alone reaches the Mediterranean. 



In examining the great delta regions in search of possible ex- 

 planation of conditions during Coal Measures times, one must not 

 confine his attention to the lowland areas ; he must consider also 

 the alluvial plains extending at times hundreds of miles above the 

 technical head of the delta, even to the region where tributaries 

 bring down coarse materials. The story is continuous from shore 

 to mountains. 



The immense plain of eastern China is described^-^ as curving 

 around the mountainous region of Shan-tung and as extending 

 southward from near Peking for about 700 miles with width of 150 



'^ Lieut. Newbold, " On the Geology of Egypt," Quart. Journ. GeoL Soc, 

 Vol. 4, 1848, pp. 341, 342. 



"*R. K. Douglas, "China," Encyc. Brittan., 9th ed.. Vol. V, p. 630. 



