368 Mr. Weaver's Geological Observations, Sfc. 



§ 49. Mining operations have also been conducted in the new red sand- 

 stone and clay marl formation ; namely^ in that part which skirts the eastern 

 borders of the Broadfield Down range. The upper part of this range, over- 

 looking the vale in which is situated the village of Winford, consists of the 

 carboniferous limestone. This is overlaid, on the brow of the hill, by a de- 

 position of the calcareo-magnesian conglomerate, which is succeeded by the 

 new red sandstone, both declining toward the vale. In the latter is found a 

 bed of that kind of clay ironstone, called reddle, which varies in thickness, 

 but in some places extends to five or six feet. To this bed, pits are sunk 

 at convenient distances, commonly about eighteen yards in depth, and 

 connected with each other by means of the underground operations, the bed 

 itself being wrought by the pickaxe in the broad-way. The works are car- 

 ried on during the dry season only, when they are free from water, being 

 flooded in the winter by the subterranean springs. The reddle thus obtained 

 is applied to various purposes ; among others to the preparation of a pig- 

 ment. 



In concluding these observations, I shall merely add, that if we consider 

 the old red conglomerate and sandstone, and the calcareo-magnesian conglo- 

 merate and sandstone, in a general point of view, with reference to their re- 

 lative position, composition, and structure, both will be found to bear evidence 

 of the violent disturbances which have taken place during the conformation 

 of the crust of the globe. The former, compounded of the detritus of more 

 ancient rocks, are spread over formations of an earlier era, reposing upon 

 and extending from those of the transition period, to the fundamental granite 

 itself; their composition varying more or less according to the constitution of 

 the tracts upon which they border : and the calcareo-magnesian conglome- 

 rate also varies in a corresponding manner, when reposing on the carboni- 

 ferous series, or spreading from thence to the confines of the transition and 

 primary formations. Analogous considerations apply to the conglomerates 

 and sandstones which are partially found in the transition and primary epochs ; 

 but with increasing force to those of the later periods in the geological suc- 

 cession, — the new red sandstone, the iron and green sandstone, and the gravel 

 and sandstones of the fourth or last sedimentary series. If such effects attest 

 a long-continued action of the ocean, subject at distant intervals of time to 

 greater or smaller degrees of agitation ; the abundance of marine remains 

 distributed throughout the whole of the secondary series, from the transition 

 beds up to the latest deposits of the ancient sea, demonstrate a similar action 

 in a still stronger manner. 



