30 NOTES ON THE CANNOCK CHASE COALFIELD 
and Lancashire the same deposit attains a thickness of 2,000-3,000 
feet. The sand, which varies very much in colour from pure white to 
yellow and deep red, is sometimes found quite loose and sometimes 
pressed into hard sandstone. The gravel varies in size from ordinary 
gravel to pebbles as large as one’s head ; sometimes it is loose and 
sometimes it is cemented by carbonate of lime into a compact hard 
conglomerate. 
The pebbles are all rounded and waterworn; they consist of 
quartzite, vein quartz, felspar grit resembling granite, porphyry. 
syenite, jasper, trap, greenstone, sandstone, limestone, and chert. 
The commonest pebble—forming perhaps 85 per cent. of the whole — 
isa hard fine-grained grey quartzite. A heap of broken pebbles by 
the roadside affords an interesting study to the student in the 
various kinds of rocks which go to make up the pebble beds. 
What strikes one most in viewing these layers of sand and 
gravel and conglomerates is the enormous waste of older rocks they 
represent. They are the result of the detrition of older deposits, 
and what we call waste is really the building up of something new, 
for in nature there is no actual waste. A chart of the British 
sedimentary rocks shows the tremendous relative thickness of the 
older groups, so that in the Triassic Age when the degradation and 
transfer was going on there was plenty of material formed for all 
future requirements. It has been estimated that the Bunter Rocks 
of Great Britain represent in volume the wastage of a range of hills 
65 miles long, 4 miles wide, and 500 feet high. Where then did all 
the material come from? Dr. Bonney, the well-known geologist. 
has devoted much time in the endeavour to determine the origin of 
these rocks, and concluded that the quartzites, which form so large a 
percentage of the pebbles are identical with existing quartzite rocks 
in the Northern and Western Highlands; he believes that the 
original source was North-West Scotland, and that the waste rocks 
had lain as pebbles on the Old Red and Carboniferous Rocks of 
Southern Scotland, until in Triassic times huge rivers swept them 
away south on to their final resting place in the Midlands and else- 
where. Against this theory is the fact that whereas the pebble beds 
of the Midlands are formed mostly of very large pebbles, in 
Cheshire and Lancashire the beds consist of gravel and sand, and 
the action of a river is always to deposit the larger rocks first, and 
earry the finer material only to the far end, 
