180 



SUMMARY OF THE CORNSTONE FORMATION. 



On the western face of the Titterstone Clee they rise to a great height both at and 

 above Bitterly Court; they surround the Brown Clee, and are largely quarried at 

 Abdon, Ditton, &c. It is not possible to include these cornstones under one minera- 

 logical description. In most places they are of red and lightish green colours ; in others, 

 however, they are light brown with veins of dark chocolate and green, a variety of which 

 in a highly crystalline form is extracted at Targrove, near Downton Hall. At Ditton, 

 white and green colours prevail ; at Bromsgrove the mass is brown, with light grey 

 patches ; while at intermediate places they consist of marl, limestone, and sandstone, 

 irregularly concreted, and have the aspect of a conglomerate. In the last-mentioned 

 form alone, they constitute the cornstones of the inhabitants, and in this state are 

 quarried exclusively for the repairs of the roads, and are not burnt for lime. The best 

 courses are, however, almost crystalline, and if polished might be considered not ine- 

 legant marble, though the concretions are usually too small to afford large slabs. In 

 some of the great works at Ditton and Abdon there are two zones, the lowest and largest 

 of which is quarried to a depth of twenty feet, in caverns under the slopes of, the Brown 

 Clee Hills. It is needless to mention other localities in this neighbourhood, for the 

 formation here ranges over a very wide area. (See Map.) 



Throughout the whole of its range, with the -exception of the space between the coal- 

 field and the older rocks of Caermarthenshire, and its protrusion through some of the 

 poor coal-fields of Bewdley Forest, the strata of this cornstone group are very little 

 inclined, an arrangement which might naturally have been looked for in the central 

 parts of a basin or trough of large size. The spotted marls can never be distinguished, 

 from those of the New Red Sandstone, except perhaps when they are separated from 

 each other by beds of hard, micaceous sandstone. In districts where the argillaceous 

 character exclusively predominates, there is some difficulty in persuading the inhabitants 

 that they live upon the Old Red Sandstone ; although that name when applied to the 

 whole system is as unobjectionable as any in the nomenclature of geology. 



Wherever the order of superposition is not apparent, the fragments of fossil fishes 

 which occur in abundance throughout the cornstones 1 , constitute the best distinction 

 between this formation and the Lower New Red Sandstone which it so much resembles. 

 These fishes, which will be described in a subsequent chapter, are of very peculiar forms, 

 and their fragments being often of brilliant purple and blue colours, are excellent points 

 of attraction for the eye of the geologist ; since they present a strong contrast to the 

 surrounding dull red and green matrix in which they are enveloped. (See PL 1 and 2., 

 in which the fishes of the genera Cephalaspis and Onchus are figured.) 



1 The fishes of the cornstone formation were first discovered hy Dr. Lloyd of Ludlow. (See Chapter on the 

 Organic Remains of the Old Red Sandstone.) 



