214 T. Stock — Keuper Conglomerate, Bristol. 



six inches, and as the drain is now filled up, the means of more 

 accurate measurement are lost. The distance from the nearest 

 denuded edge of the Coal-measures is as nearly as possible half a 

 mile. Also, in making a drain-cutting in Heath Street, connecting 

 the two Eastvilles, and about a quarter of a mile nearer Stapleton 

 than the last, but about the same distance from the Coal-measures, 

 another conglomeratic bed was exposed, in which, however, the 

 quartz pebbles were smaller. As the Keuper beds lie horizontally, 

 or nearly so, in this district, the second bed may be a continuation 

 of the first, the altitudes being approximately similar. There is 

 nothing to show that this conglomerate differs much from most 

 others, in respect of derivation, being probably composed of the 

 worn-down materials of preexisting formations, of rocks perhaps for 

 the most part of Coal-measure age. The fineness of the conglome- 

 rate would naturally be attributed to its greater distance from the 

 shore. The traces of green clay or shale may be referred with some 

 probability to the Coal-measure shales, which are often variegated in 

 this vicinity and highly coloured, as may be seen in the section 

 at the Easton Brickworks and elsewhere. Apart from the question 

 of conglomerates, I think I have evidence, which requires however 

 to be carefully weighed and reexamined, of the using up of 

 contemporary materials, in the formation of certain Jurassic and 

 Coal-measure shales, in which there Avas, as is well known, frequent 

 subsidence and elevation. The evidence to which I refer is a few 

 instances in Somersetshire and Gloucestershire of well-preserved 

 fossils occurring upon natural casts of fossils, and the occurrence of 

 what I believe are pebbles of coal. 



I may also mention that I have obtained or seen a good many 

 quartz pebbles in the Ehsetic bone breccia at Aust ; but as I have not 

 access to much of the literature of the Eh^tic, I cannot say whether 

 the fact has been noted or not by others before. 



2. A Dolomitic'? Breccia in the parish of Alveston, Gloucestershire. 

 — My friend Mr. Olive, of Greenhill, lately drew my attention to an 

 interesting little section exposed whilst making a boundary-wall 

 on his property. It consists of a series of thin beds lying horizon- 

 tally, the upper ones being much brecciated, the thick basement bed 

 being homogeneous. The included fragments of the neighbouring 

 Carboniferous Limestone are distinctly angular, being in fact distinctly 

 a breccia, and not a conglomerate. One would naturally suppose 

 that this must be an outlier or continuation of the neighbouring 

 dolomitic conglomerate, which is marked on the Geological Survey 

 Map as running up triangularly to near this spot. If so, it is 

 interesting as an example of a conglomerate passing into a breccia, 

 on account of its closeness to neighbouring Carboniferous Limestone 

 cliiFs. The bedding is also interesting, as also its (apparent) 

 liorizontality. I do not feel sure whether it may not be a breccia 

 of later age. The matrix is apparently dolomitic, approaching, 

 however, in appearance, some of the Lower Liassic or even Oolitic 

 beds ; but I must leave the matter in the hands of more experienced 

 geologists. 



