C. MOORE OK ABNORMAL GEOLOGICAL 



in depressions on the edges of the inclined Carboniferous Limestone. 

 They are separated by thin blue clays with Avicula contorta and 

 also Distinct Babiana. I have no doubt they would yield important 

 vertebrate remains, as I found a very perfect Dinosaurian vertebra ; 

 but, unfortunately, these beds have not been worked for some years. 

 Vertical mineralized infillings are present, passing down through the 

 Carboniferous Limestone in this section. In the southern corner, but 

 occupying a higher position than these conglomerates, there is a 

 patch of close-grained cream-coloured limestone undistinguishable 

 from the White Lias ; but it has yielded me no trace of organic re- 

 mains. The deposits of one section usually differ from those in 

 another, or die out altogether, although they may be in close proxi- 

 mity. Eor instance, in the next quarry the conglomerate is a single 

 thick, dense bed, with pebbles united by calcareous matrix, in which 

 are occasional nests of Estheria minuta and insects, whilst above are 

 a few inches representing the Lower Lias, capped by about 10 feet of 

 Inferior Oolite. 



In addition to the unconformable Secondary deposits which lie on 

 the Carboniferous Limestone, a special feature of the latter formation 

 is the many vertical fissures passing down through it, with infillings 

 containing Secondary remains, or those of a still later age. In the 

 Vallis these veins are best seen in the face of a large quarry at Egg- 

 ford, where, in addition to several smaller ones, the workings are 

 bounded by veins at both ends, that on the north being of some 

 thickness, and showing a vertical side about 50 feet in height, where 

 it meets a patch of Inferior Oolite. The matrix of this vein is Liassic ; 

 and numerous organisms may be traced in it. All the veins are much 

 mineralized, and contain sulphate of barytes in concretionary layers, 

 with occasional traces of galena and blende. At Elm and at JNunney 

 haematite iron-ore has been extracted ; at the latter place in close 

 proximity to a deposit of Inferior Oolite. 



The hamlet of Holwell occupies a depression at the southern end 

 of the Yallis gorge, and is on every side surrounded by sections 

 which, if looked down upon from a little distance, without closer 

 inspection, would appear to most geologists to be entirely composed 

 of Carboniferous Limestone. The road from Erome to Shepton 

 Mallet passes through this spot, and crosses the little stream from 

 which the hamlet is named. On the eastern side are two quarries I 

 have already described*, viz. : — that of the Marston road, in which, 

 within a few yards, are present stratified Inferior Oolite, Liassic con- 

 glomerate (with many organisms), and a thin band of Rhsetic clay, all 

 resting on Carboniferous Limestone, with a thick vein filled with calc- 

 spar in their midst ; and also a large quarry below, with a face pa- 

 rallel to the stream, in which are to be seen many vertical dykes, 

 some with Rhaetic and others with Liassic organisms f . They present 

 much mineralogical variety ; and the somewhat impure limestone 



* " Abnormal Conditions " &c, Quart. Journ. Geol. Soc. vol. xxiii. (1867) 

 p. 483. 



t A section of this has been given in "Abnormal Conditions" &c, Qitart. 

 Journ. Geol. Soc, 1867, p. 484. 



