178 CORN STONE FORMATION, SHROPSHIRE, WORCESTERSHIRE, ETC. 



stone, or the firmest ribs of sandstone. In the northern portion of this range, the sub- 

 ordinate limestones become thicker and more crystalline. 



Bands of cornstone appear at intervals in all the country lying between the Clee Hills and the 

 southern extremity of the coal-field of Coalbrook Dale; the same suite of beds forms also the base 

 upon which the greater part of the coal tracts of Billingsley and the Forest of Wyre have been de- 

 posited. At Lower Harcott, on the west side of Kinlett, the cornstone dips south and south-south- 

 west forty-five degrees, is five or six feet thick, and is burnt for lime. It here reposes upon a good 

 sandstone of greenish colour. This cornstone, as in other parts, is of very irregular dimensions, 

 contracting and expanding in the most capricious manner. In one district only I have traced it on 

 the east bank of the Severn, where the existence of the Old Red Sandstone had not previously been 

 noted in geological maps. (See Map and Section, PI. 30. fig. 3.) 



The formation is there displayed in a narrow and detached ridge on the south side of the thin 

 zone of coal measures of Arley and Shatterford, ranging between these rocks and the New Red 

 Sandstone of Warshill and Horsley Bank near Kidderminster. The Old and New Red Sandstones 

 are in abrupt and unconformable junction on the sides of a new cut in the road ascending from Kid- 

 derminster to Shatterford Gate, near which beds of true cornstone are burnt for lime. These beds 

 are there clearly distinguishable from the calcareous bands of the adjacent Lower New Red Sand- 

 stone, by their unconformable position. 



The extent of the changes made in the map of the boundary lines of previous ob- 

 servers, defining the junction of the Old, and the contiguous New Red Sandstone of 

 Worcestershire, can be best understood by comparison with such authorities. Much 

 ambiguity, indeed, prevailed in this part of the region, owing to the anomalous litholo- 

 gical characters of the Lower New Red Sandstone, (already explained in chapter 4.,) 

 which, on the confines of Worcestershire, Salop, and Herefordshire, puts on so much 

 the character of the Old Red, with which it is in contact. 



On the right bank of the Teme, the hills of Old Red Sandstone, ranging from Tenbury to the 

 villages of Stamford and Shelsley Walsall to Sapey, &c, consist of marls, clays, sandstones, and 

 flags, with some thick zones of concretionary limestone. In one of these bands near Hill Top, east 

 of Tenbury, I found the crevices partially filled with minute thin coats of anthracite, mixed with 

 white crystallized carbonate of lime. Besides the principal bands of limestone, which here vary in 

 thickness from four to ten feet, there are, as in other places, thinner courses of cornstone, alternating 

 with beds of deep red and greenish sandstones, of a flaggy structure. Much calcareous matter is 

 disseminated throughout these hills, and gives rise to the superficial deposit of travertine and sta- 

 lactite which will be described in a subsequent Chapter. (See Southstone Roch, Index.) 



The sandstones associated with the marls and cornstones sometimes expose upon 

 their surfaces certain small depressions, frequently of circular and horse-shoe forms, 

 occasionally having a raised central disc. These forms, which are remarkably exhibited 

 in the bed of the Sapey Brook, near Knightsford Bridge, appear to be due to the action 

 of water upon blotches, or imperfect concretions of party-coloured marls or soft argilla- 

 ceous sandstones, which being of less consistence than the mass of the rock, have been 

 eroded, leaving these cavities. Similar forms, indeed, are found in numberless portions 



