162 E. C. Martin — Source of Limedone Pebbles 



Limestone and probably joined to the Mendip Hills by limestone 

 ridges, of which fragments still remain in the islands in the Bristol 

 Channel. 



In June, 1907, in a small conglomerate quarry at the south end of 

 Langford Heathfield, I noticed several limestone pebbles with Corals 

 and Brachiopods, which suggested Carboniferous Limestone of Mendip 

 type rather than the Culm limestone. During two recent visits to 

 "Wiveliscombe I was able to collect fossiliferous pebbles from several 

 localities between Thorne St. Margaret and Williton. In the following 

 notes I have briefly described the fossils obtained (the localities being 

 taken from south to north) and have then discussed their bearing on 

 the origin of the conglomerate. 



Description of the Fossiliferous Fellies. 



Thorne St. Margaret. — Several more or less silicified limestone 

 pebbles with crinoid fragments and badly preserved Brachiopods 

 were found in an old quarry north of the church by the road to 

 Kittisford. 



Langford, Heathfield. — In the small quarry at the south end of the 

 Heathfield I found a large limestone pebble with Stjringo-pora (closely 

 resembling 8. ramulosa, Groldfuss). Another pebble of very hard 

 limestone showed Spiriferids on the weathered surface. 



Colhaxj. — Fossiliferous limestone pebbles, with crinoid fragments, 

 Spiriferids, etc., are common in an old quarry south of Cobhay Farm, 

 near Bathealton, but the limestone is so hard that the fossils cannot 

 be extracted, and it is only on the weathered surfaces that the fossili- 

 ferous nature of the stone becomes apparent. Amongst the fragments 

 in this quarry I found a beautifully weathered out piece of silicified 

 limestone with small crinoid fragments and Bryozoa (Fenestellids and 

 Rhaldomeson or Rhomlopora) ; its appearance strongly suggested some 

 of the beds in the Lower Carboniferous Limestone of the Bristol area. 



Owing to a fault the Bunter Conglomerate at Cobhay is brought 

 close to the Lower Breccio-Conglomerate subdivision, which can 

 be examined in a small quarry east of the farm. In both divisions 

 the limestone pebbles are fairly well rounded and bear a general 

 resemblance to one another, but are usually much smaller in the 

 lower division. 



Milverton. — In the large quarry north of Milverton railway station 

 I found two pebbles of hard, unaltered limestone, showing sections of 

 Zaphrentis. About a mile further north, in a quarry east of the road 

 to Halse, a slightly silicified limestone pebble with a portion of 

 a large Froductus was found. 



Wiveliscomle. — In Castle and Tipnoller Quarries, north-east of 

 "Wiveliscombe, fossiliferous limestone pebbles, more or less silicified, 

 are common. In some cases the silicification has only extended to the 

 fossils, which can be extracted in a more or less fragmentary condition 

 by dissolving out the matrix with dilute hydrochloric acid. In these 

 pebbles I found circular and pentagonal crinoid sections, Brachiopods 

 (Spiriferids, cf. Chonetes Hardrensis, etc.), and a Grasteropod resembling 

 Capulus. In other cases the whole pebble is silicified ; one of these 

 contained crinoid fragments and Bryozoa {Fenestella, Rhaldomeson ?). 



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