178 MENDIP NOTES. 



DURSDONj NEAR WOOKEY. 



Geologists are well acquainted with the line face of Dolo- 

 initic Conglomerate, here forming the basement beds of the 

 Trias, beneath which the Wookey stream issues. This 

 Dolomitic Conglomerate occupies an old valley stretching 

 up into the Mendips as far as Dursdon. When the Mendips 

 were sinking slowly and gradually beneath the waters of 

 the Triassic sea or lake, the fragments which strewed the 

 sides of the hills were collected into this fringing deposit 

 which here and there, as in the old Wookey Valley, forms 

 tongues or inlets into the Palaeozoic area now exposed by a 

 later denudation. 



Near the upper end of this tongue there are well-marked, 

 and now well-exposed, deposits of iron ore and mangani- 

 ferous iron ore which are being worked by the Soinerset- 

 sliire Manganese and Iron Company. The deposits are very 

 irregular, and occur mainly in the Dolomitic Conglomerate. 

 But they are also described as passing down into the under- 

 lying Mountain Limestone, whether as lodes or as infillings 

 of cracks from the surface is uncertain. I incline to the 

 latter view. There are also sparry veins containing little 

 strings of Galena. The locality is well worth a visit, and 

 I have to thank Col. Harcourt and the Secretary of the 

 Company, Mr. J. Bicknell, for kindly giving me the oppor- 

 tunity of examining it. 



Cheddar. 



" Old Ked Sandstone of a very compact nature occurs 

 about one mile to the South-east of Cheddar, accounted for 

 probably by a fault. The surface of the ground is sloping 

 and much overgrown with furze, but the stone has been 

 quarried in two or three places where tolerably good sections 

 are exposed." (" Survey Memoir of East Somerset," etc., 

 p. 16. From Mr. Blake's Notes.) 



