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By JOEL LEAN, Assoc. M. Inst. C.E. 

 Bead February 2'2nd, 1888. 



IN tlio neighbourhood of Bristol the Dolomitic Conglome- 

 rato will be found lying against the upturned edges of 

 the Carboniferous Limestone in nearly every case, the chief 

 exceptions being from Sncyd Park towards Portisliead, and 

 along the coast from Portisliead to Glevedon, where it lies 

 against the Old lied Sandstone. 



The Avon, in its course from Bristol to the Severn, 

 runs successively through the Carboniferous Limestone, the 

 Old Red Sandstone, the Dolomitic Conglomerate and the 

 Keuper, or Red Marl, from which it emerges near Sliire- 

 hampton into the alluvium bordering the Severn. A peculiar 

 development of the Dolomitic Conglomerate is found at the 

 villaf>-e of Almondsbury, which is situated almost entirely 

 upon it, where it swells out from a narrow strip to (juito a 

 large area. At this place there used to bo worked a rather 

 fine quarry of the Conglomerate; and some fine blocks from 

 thence were used in tlio building of the bridge under the 

 South Wales Union Railway near Cattybrook Farm. Its 

 e:!ftremely partial and local development was peculiarly 

 shown in the construction of the new tunnel on the before- 



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