11 



On some Sections of the Lias and Sands exposed in the sewerage works 

 recently executed at Stroud. Bead at May Hill, by E. Witchell, F. G. S., 

 Stroud. 



The sewerage works recently executed in and adjacent to the town of 

 Stroud have afforded an opportunity for examining the TJpper and Middle 

 lias, and the Sands beneath the Inferior Oolite in that locality. The 

 excavations were altogether upwards of a mile and a half in length. 

 The section subjoined shews the depths of the strata from their elevation 

 above the sea level. The lowest point of the excavations was at the 

 filtering tanks below the town, the floors of which are at an elevation of 

 101 feet, and the highest trench on Stroudhill was about 500 feet. 



The lower portion of the section, numbers 10 to 18, though taken from 

 an excavation of 80 feet in length only, may be considered as shewing the 

 strata of the valley of the river Frome below Stroud. Taken in descending 

 order, we find buff coloured clay four feet, gravel four feet, blue marl two 

 feet, marlstone six to seven feet, and the marls of the Lower Lias. It may 

 be here remarked, that in a recent unsuccessful attempt to find water, 

 made in the neighbouring mUl-yard at Fromehall, the Lias was bored to 

 the depth of 460 feet before the work was abandoned. 



The buff-coloured clay and gravel are recent formations ; the gravel 

 though probably brought from the larger deposit known as the Stroud gravel 

 bed, which bounds the vaUey on the north side and is situated at a higher 

 level, is nevertheless a distinct bed, inasmuch as it contains drifts of leaves 

 forming a peaty deposit in which were found firagments of land shells and 

 branches of trees, also bones, antlers, &c., in their natural state, whereas 

 the larger gravel bed consists of pure gravel and contains none of 

 these deposits. 



The Lias marl overlying the rock contained a thin stratum of brown 

 earth and nodules formed of clusters of fossU casts cemented together, also 

 water-worn limestones, the whole forming a band about three inches thick. 

 The casts were chiefly those of young Ammonites capricornus, Schloth., 

 Cucullcea Miinsteri, (the latter in large quantities), Pleuromym, Gryphea 

 cymbium, and Pecten mquivahis, Sow. 



Below this band at a depth of about nine inches was another of a 

 different character, composed almost exclusively of valves of Oryphaa 

 eymhium. The shells were entire when uncovered but soon broke up into 

 fragments. It was observed that the marl lying upon this bed separated 



