696 Geological Society. 



and wherever there are any sections at right angles to the contours, 

 the rock-slopes are seen to be remarkably steep. Contoured maps 

 have been prepared, showing the features of some of these covered 

 peaks. 



On the buried slopes, and in the gullies, are screes and breccias : 

 and bands of stones and grit are present in the adjacent beds of 

 marl. All these stones, in every case, are derived only from the 

 rock immediately at hand. They never resemble pebbles, but often 

 are fretted into irregular shapes. Where exposed to the present 

 climate, the Charnian igneous rocks are deeply weathered and 

 disintegrated. But the same rocks beneath the Keuper are fresh 

 right up to the top, as also are the rock-fragments in the marls. 



The Keuper marls lie in a catenary manner across the gullies, 

 and probably across the large valleys also ; for they dip away 

 steeply in all directions around each buried peak. 



There has been almost no post-Triassic movement in Charnwood. 

 Nevertheless, the beds must have been originally laid down 

 horizontally, for they are in no way peculiar, and contain the 

 normal seams of shallow-water sediment. All the points of contact 

 of any one bed with the Charnian rocks lie on one horizontal plane. 

 The inclination of the strata must, therefore, be due to subsequent 

 sagging. 



The Upper Keuper deposits accumulated in a desert basin, of 

 which parts were dry and parts were occupied by ever-shifting 

 salt-lakes and pools. In these waters the red marls were laid 

 down. The red marls are of several different types, and are 

 usually well-bedded. The principal ingredients are a certain 

 aluminous mineral in very small particles and a much smaller 

 proportion of very fine quartz-sand. There is generally 20 or 

 30 per cent, of dolomite present, in the form of minute rhombs. 



The grey bands include various kinds of rock. Each band 

 usually contains one or more seams of well-bedded sandstone or 

 quartzose dolomite, and may safely be relied upon to indicate the 

 bedding. The irregularities are due to irregularity in the bleaching 

 above and below these porous seams. 



The abundant heavy minerals are garnet, zircon, tourmaline, 

 staurolite, rutile, magnetite. These are found in every sediment — ■ 

 marls, sandstones, grits, breccias, etc. The grains are intensely worn. 



The quartz-grains are sometimes evidently wind-worn. The 

 sand in the grey bands is coarser and more abundant than that 

 in the red marls. Each grey band marks the introduction of 

 coarser sediment into the basin. The false bedding is mainly from 

 the south-west. The bands are of wide extent and are due to 

 inflows of fresh water from the surrounding hills, which from time 

 to time spread themselves far and wide over the dry portions of the 

 desert, and were often completely desiccated before reaching any 

 pre-existing pool. Where these waters evaporated the quartzose- 

 dolomite seams were formed, bearing ripple-marks and salt- 

 pseudomorphs. The ripples indicate prevalent south-westerly winds. 



