Vol. 59.] SOUTH DEVON AND THE MIDLANDS. 323 



IY. The Buntek Conglomekate of the Midlands. 



This very distinct deposit has long attracted attention, but 

 without evoking much serious or systematic study until recent 

 years. The Geological Survey Memoir in 1869, however, devoted 

 some pages to it. In 1880, 1 and in numerous subsequent papers, 

 Prof. Bonney dealt especially with the lithology of the pebbles and 

 their physical history, yet very little has been done beyond the 

 work accomplished by Prof. Bonney himself in the way of deter- 

 mining species. This is somewhat singular, when it is considered 

 that fossil-evidence is usually regarded as the most trustworthy of 

 all geological data, and that a comparatively rich fauna in the 

 Budleigh-Salterton pebbles was known to us nearly forty years 

 ago. 



The Midland Bunter, where it is most typically represented, 

 has certainly a strong general likeness to that of Devon. I was 

 impressed by that resemblance when visiting the quarries at 

 Exmouth and Repton respectively. I did not make a minute 

 analysis in the former case ; but an examination of 100 large 

 pebbles from the pit near the village of Repton gave the following 

 result : — 



Pebbles from Repton Quarry. 



Per cent. 



Crushed or brecciated quartz-rock 1 



Quartz u 4 



Quartzite, purple and brown ., , 39) «o 



Quartzite of various colours 34 J 



Purple and other grit 7 



Sandstone 6 



Compact rock, not precisely determined , 8 



Quartz-felspar grit 1 



100 



Although probably the next hundred of pebbles would have 

 given a slightly different analysis, the above may suffice to give a 

 general idea of the composition of the pebbles in this part of the 

 Midlands ; and it probably holds good in a general way for other 

 districts. It amounts to this, that 80 per cent, of the largest 

 stones consist of the quartzites and grits, many of which are of the 

 characteristic purple colour ; and it is these which must demand our 

 principal attention when instituting a comparison. 



An examination of the smaller stones would have given some- 

 what different results. Por instance, in the above there is very 

 little vein-quartz and no tourmaline-grit, the latter of which 

 certainly occurs. And Prof. Bonney informs me that felstones are 

 not rare all over Cannock Chase, and other igneous rocks are found, 

 although they are scarce and (if granitoid) rotten. 



An idea of the material of the Bunter was also obtained from 



1 G-eol. Mag. dec. 2, vol. vii, p. 404. 

 Q. J. G. S. No. 235. 2 a 



