192 Mr. AiKiN 071 the Wrck'in and on the 



three or four miles above Bridgenorth, and accompanies its course to 

 Wire forest, the extreme south-eastern point of the county. The 

 eastern limit of this tract extends into Staffordshire, approaching 

 within a few miles of the county-town, whence it proceeds south to 

 the village of Tettenhall near Wolverhampton, and then passes by 

 Kidderminster to beyond Droitwich. 



This rock consists for the most part of rather fine grains of quartz 

 with a few spangles of mica, cemented by clay and oxyd of iron. 

 Its colour is generally brownish-red, and it has but little cohesion ; 

 on which account large tracts of loose deep sand are found in many 

 parts of it. Sometimes it occurs nearly of a cream colour, and Is 

 then sufficiently hard to form an excellent building stone : it does 

 not effervesce with acids, and, to the best of my knowledge, never 

 contains shells or other organic remains. Rolled stones of quartz, of 

 granite, of greenstone-porphyry, and of other primitive rocks, are 

 found dispersed over its surface and imbedded in the loose sand, but 

 are rarely, if ever, observed at any considerable depth in the solid 

 rock. It rises at an angle of 10" or 12° between S. and S.W. At 

 Alderley Edge in Cheshire, it is mixed with grey oxyd of cobalt, and 

 contains veins of heavy spar with galena and yellow copper ore ; and 

 is tinged green by oxyd of copper at Hawkestone, at Pym-hill, and 

 elsewhere in Shropshire. The salt deposit of Northwich, and the 

 salt-springs of Droitwich, of Adderley near Drayton, and of Admas- 

 ton and Kingley-wich near Wellington are subordinate to this for- 

 mation. Its southern extremity in Shropshire rests upon highly 

 elevated strata of grauwacke. It is covered in several places by thia 

 strata of sandstone- slate, which passes into slaty marl containing shells : 

 these beds rise in the same direction as the sandstone on which they 

 rest, but with an angle rarely exceeding 6°. The general face of 

 this tract is an undulated country, having usually the southern decli- 



