THE SOUTH STAFFORDSHIRE COAL-FIELD. 249 



tive drawings, some of which were contrived, by means of moveable 

 parts, to exhibit the gradual progress of the changes of which he 

 spoke; one of the most striking of these was a map of part of 

 South Staffordshire, which anticipated one of the suggestions of Mr. 

 Wyse for facilitating the comprehension of geological topography. 

 It exhibited at first a uniform colouring, expressive of the red 

 sandstone with which the surface is covered ; and several layers were 

 successively removed from the part indicative of the coal field, co- 

 loured so as to give an idea of the coal, the rock measures, the iron- 

 stone, the clays, &c., down to the prevalent bed of limestone ; por- 

 tions of the layers being cut out, in order to exhibit, in their proper 

 situations, the coal, the basalt, and the lime, which are occasionally 

 seen at the surface. 



The second lecture was commenced by reference to a large and 

 elaborately-constructed section, formed on careful observation and 

 inquiry, and presenting a general idea of.the condition of the strata 

 through the coal field, could they have been examined immediately 

 after the great elevations and depressions of their parts. A remov- 

 al of a portion of the drawing exhibited afterwards to the eye, in a 

 lively manner, the new line of surface, shewing the result of the 

 gradual operation of air and water, in reducing the rough and pre- 

 cipitous ridges, filling up deep cavities, and producing the undulat- 

 ing line which now prevails.* 



The relation of such a spectacle to the evenly deposited strata of 

 a coal basin, in its original form, was pointed out, and the numerous 

 interesting geological facts included within the range of the section 

 adverted to ; shewing instances of dislocations or " faults," by which 

 the corresponding measures were thrown to a difference of level, 

 amounting, in some instances, to a hundred yards ; fissures or 

 " dykes," filled up with injected veins of originally fused matter, 

 now bearing the form of hard and closely-grained rock, interrupting 

 the work of the miner, and occasionally bursting through the entire 

 strata, and forming hilly protuberances on the surface ; the eleva- 

 tions of the solid ribs of limestone into the anticlinal position, or 

 sloping each way, at the Wren's Nest and Dudley Castle Hills, 

 where these ocean beds are raised to angles of thirty, fifty, and eighty 

 degrees ; the coal measures, uniformly prevalent over the cavity of 

 the basin, but broken and dispersed at the elevated ridges, dividing 



• This magnified section %vas, in fact, with more of detail, generally simi- 

 lar to the one which is given by Mr. S. in his Binuingham and its Vicinity, 

 and which will be found in our number for Ajiril, 1837, accompanying a 

 notice of that work. — En. 



