Part of Gloucestershire and Somersetshire. 361 



sandy particles. All these beds contain organic remains,, similar to those 

 that occur in the continuous limestone, particularly spiriferites, terebratulites, 

 and entrochites, with some corallites ; and I have met also with one small 

 orthoceratite. The slate-clay, however, contains such remains much more 

 rarely than the other beds. 



The southern body of slate-clay, which seems of smaller dimensions, but 

 not determinable, appears under analogous circumstances, wherever suffi- 

 ciently exposed to admit of observation, as in the bye-road to the east of 

 Winscombe church. Upon this range of slate-clay, fruitless attempts were 

 formerly made to discover coal. 



The continuous limestone on the southern side of Mendip is generally dis- 

 posed in strata varying from six inches to five feet thick ; on the northern side, 

 in strata from six inches to three feet thick. It is commonly of a blueish gray 

 colour, sometimes tinged with black, and more rarely, mottled with red ; and 

 is not unfrequently fetid. It contains incidentally slight layers and masses of 

 hornstone and lydian stone ; and also beds of magnesian limestone, of variable 

 thickness. The limestone of the northern range, as traversed by Burrington 

 comb and the ravines connected with it, appears to be about 600 fathoms 

 wide. In its central part is interposed a bed of magnesian limestone, about 

 ten fathoms thick, of an ash gray colour, granularly foliated or compact, and 

 when in a state of disintegration, resembling sandstone. But more to the 

 west, in the Sandford and Banwell portions of the ridge, the magnesian lime- 

 stone obtains a much more considerable width, probably not less than one 

 hundred fathoms. It here exhibits reddish brown, ash gray, and buff yellow 

 colours, and frequent cavities lined with crystals of calcareous spar. The 

 organic substances which it contains consist principally of caryophyllites. 

 Beds of magnesian limestone are also to be met with in the southern range ; 

 e. g. adjacent to the road leading to Cross, and in the southern side of Blea- 

 don hill. Its most common structure is the minute-foliated granular. 



The organic remains which I have observed in the Mendip limestone are 

 the following * : — 



* It may be useful to notice in this place the remains of fish that have been met with in other 

 parts of the world, both in the carboniferous limestone and in the coal formation : 



In England, — as above stated, and palates and bones near Bristol, in the carboniferous lime- 

 stone. (Geol. Trans. Vol. IV. p. 198 and 200.) 



In Scotland, impressions of fish, and teeth of fish in the limestone of the coal formation. 

 (Essai Geologique sur I'Ecosse, par Boue, p. 172, 195.) 



In Ireland, casts of the concavity of the vertebrae of fish, in the limestone near Cork. (Mr, 

 Miller's collection.) In 



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