114 Rev. A. Sedgwick on the Geological Relations and 



The whole country between Robin Hood's Well and Wentbridge, is inter- 

 sected by great dislocations, which have altered the position of the beds, and 

 modified the whole surface of the country*. Jst. A great north and south 

 fault, producing- an enormous upcast to the east, brings in the lower gypsum 

 behind the village of Askernef . '2nd. A great east and west fault crosses the 

 North road, ranges on the south side of Upton Beacon, and throws the plateau 

 of North Elmsall below its natural level. 3rd. A similar fault crosses the road 

 at the Robin Hood House, and throws the upper beds, with an inverted dip, 

 below the level of the yellow limestone. 4th. A similar break (and perhaps a 

 prolongation of the preceding) appears at Stubbs Hill, at which place there is 

 also a second break producing a downcast in the opposite direction;};. 



A considerable dislocation, ranging- east and west near Sherburn, has 

 brought up the yellow limestone of Huddlestone quarry, &c. to the level of 

 the higher series§. There are also several indications of extensive dislocations 

 among the beds appearing in the banks of the rivers which traverse the forma- 

 tion. For example, on the banks of the Nid, in the escarpment below Maltby ; 

 on the banks of the rivulet below South Anston, &c. &c. In some of these in- 

 stances it seems probable that the direction of the transverse valleys has been 

 in a great measure determined by the direction of certain lines of fault which 

 were formed anterior to their excavation ; for denuding currents would act 

 more readily upon the broken edges than upon the solid beds of secondary 

 deposits ; and faults would therefore prepare the way for future valleys. 



Lastly, there are some very remarkable contortions and breaks of the strata 

 on the coast of Durham, between Black Rocks and Hartlepool ; but they are 

 perhaps on too small a scale to be mentioned in this place ; and an adequate 

 notion of them cannot easily be conveyed by verbal description. 



Minerals found in the several deposits subordinate to the Magnesian 

 Limestone. — Mineral Springs . 



I. Ores of iron. — 1. Hydrate of iron appears to form the colouring matter of many of the 

 yellow beds of limestone ; also of many of the beds of marl and sandstone, — more rarely in nodular 

 concretions. 2. Red oxyd of iron., less generally diffused than the preceding, forms the greater 

 part of the colouring matter of the lower gypseous marls, also of many of the red beds in other 

 parts of the series ; rarely seen as a haematite ; in that form associated with sulphate of barytes, 

 and traversing the yellow limestone of Bramham Moor in thin veins. 3. Black oxyd, constantly 

 associated with the various beds of No. 3. and No, 5. in the form of black spots, generally stel- 

 lated, and of dendritic impressions ; rarely forms the colouring matter of considerable masses. 

 4. Iron pyrites, rare, found in marls subordinate to No. 3. under Burton Leonard; also near 



* Plate IV. No. 3. t Plate IV. Section 2. 



+ Plate IV. Section 3. § Plate IV. No. 2. 



