86 EEV. ED"\VIN HILL AND TEOr. T. G. EONXEiT ON THE 



merate, the first is not often suggested, and it is never conspicuous. 

 A sphcrulitic structure, not indeed very distinct, has once occurred, 

 and this is in a pebhle, obtained only in 1890, from one of the bands 

 of conglomerate at Hanging llocks. 



The exterior of the fragments is seldom at all scoriaceous ; often, 

 especially in the larger, it is quite smooth. In the examination of 

 some ten dozen slides of pyroclastic rock from Charnwood, Professor 

 Eonney has never come across a fragment which was indubitably 

 vesicular. This seems indicative of a rather general absence of water 

 from the volcanic foci which supplied the materials *. 



5. Bardon Quarry. — During the past ten years the great quarry at 

 Bardon Hill has been much enlarged. The owners have afforded 

 us every facility on each of our visits ; but in so busy a place 

 minute examination is rather difficult, and we have never found 

 ourselves able to be there when the workmen were absent. At the 

 present time (1890) the quarry is divided into three stages, the 

 lowest and smallest of which has been opened since 1880. It lies 

 rather on the northern side of the common axis of the quarry. 

 The points which were chiefly studied during our visits were — 

 (i.) the order of occurrence of the rock masses, (ii.) their nature, 

 whether indurated pyroclastic or somewhat altered igneous rocks. 



As regards (i.), we are now convinced that formerly we mistook 

 the significance of the " shaly bands," in regarding them as indi- 

 cative of bedding. Purther examination in the light of new know- 

 ledge has satisfied us that these schistose beds are only " crush- 

 bands," where the rock has yielded to exceptional pressure. This 

 has produced a rude cleavage, on the surfaces of which a filmy 

 micaceous mineral has been rather largely developed, probablj' at a 

 subsequent period, by the percolation of water t. But, fortunately, 

 this error does not very seriously aff'ect our description of the pit J. 

 We then regarded these bands as indicating a general dip of the 

 beds to a point a little IsT. of N.N.E., but now, so far as we can 

 trust the indications of succession, we consider the dip to be very 

 nearly north. 



(ii.) At each visit we carefully recorded our impressions as to the 

 nature of the rocks and their apparent succession. To describe these 

 in detail would be tedious, and perhaps needless ; therefore we 

 content ourselves with a summarj- of the results, requesting future 

 visitors to remember that not a few of the data on which our con- 

 clusions are founded have disa^^peared concurrently with the exten- 

 sion of the excavations. 



To the south of the middle pit rises the knoll of breccia described 

 in our papers for 1877-78. The matrix is a volcanic ash, containing 

 fragments of slate, mostly purple, but sometimes greenish in colour, 

 which vary in size, but are occasionally over 1 foot long, and in one 



* See Professor Judd's suggestive remarks on the laxas of Krakatoa, Geol. 

 Mag. dec. iii. vol. v. (1888) p. ()84. 



t On the southern side, in 1889, we were able to eiiamine a part where the 

 rock had been less sevei'ely crushed, and found that it was really identical with 

 the brecciated rock of that part of the pit. 



\ Quart. Journ. Gool. Soc. vol. \xxiii. (1877) p. 789. 



