NORTH-WEST OF ENGLAND AND NORTH WALES. 103 



snbaerial clay and soil capping the whole. Below the foot-bridge a 

 section in the same brook shows Boulder-clay overlain by a foxy- 

 brown sand. Higher up the Bibble than Bezza Brook, and on its left 

 bank, where the river with a great sweep cuts into its bank, is a 

 very steep section of sandy drift and clay, loose and denuded by the 

 river sweeping its base. The sand is seen to rest on the Triassic rock 

 just above the level of the river. 



At Bibchester, on the right bank of the Eibble, some instructive 

 sections are seen ; and here we find a lower bed of a different charac- 

 ter come in, gradually developing up to Mitton Bridge, where it may 

 be observed in greater force. 



This lower bed, A (fig. 21), consists of rounded boulders and pebbles 

 of Carboniferous sandstones and limestones overlain by a stiff brown 

 clay, B ; C is alluvium. Not far from this section, on the same side 



Fig. 21. — Section in the left bank of the Bibble, near Bibchester. 



<So V^O-oO^.o 



Surface of water. 



A. Boulders and pebbles of carboniferous rocks. 



B. Stiff brown clay. C. Alluvium. 



of the river, this boulder-drift lies upon a blue Till, containing coal- 

 shales. 



This Till has in it oblique bands of a brown clay; above it is a 

 laminated clay, an alluvial clay capping the whole. 



On the opposite side, or left bank, we see a reddish-coloured sand 

 resting upon the irregular surface of the blue Till ; and at another 

 part of the same cliff the blue Till is seen to rest upon curved and 

 distorted shales. 



Below Whalley, on the left bank of the Calder, before it joins the 

 Eibble, a cliff about 10 feet high shows a bed of sand and gravel 

 with Carboniferous-grit boulders, and a few Carboniferous-limestone 

 boulders and some of a very fine hard grit. Following the Calder, 

 on the right bank above Whalley, on the road to Padiham, there is a 

 sand-pit showing a face of sand 15 feet high, unbottomed. The sand 

 drift contains few stones ; but bits of coal are distributed through it. 

 Further on slips in the road (which follows the valley-side) show that 

 drift of this nature continues for some distance. 



Near to Padiham, by Huntroyde Brook, a quarry by the road-side 

 showed reddish-brown clay with a few pebbles (the general top-clay 

 of the district), lying upon the Carboniferous sandstone rocks. 



Beturning down the Calder, at Cock Bridge (left bank), is a very 

 interesting section. Here the rounded-boulder bed B (fig. 22), con- 

 sisting almost entirely of Carboniferous sandstones, is capped with sand 

 mixed with blue argillaceous matter, C, and it rests upon a very hard 



