LOWER OLD RED SANDSTONE. 121 



succession, for the Brownstones overlap the Rowlestone beds both 

 on the Scyridd, and the Sugar Loaf. It is on this line of break 

 that denudation appears to have been arrested throughout a large 

 area of the Cornstone hills of Herefordshire and Monmouthshire."^ 



The Old Red Sandstone may be traced near Berkeley in 

 Gloucestershire, where, according to Mr. T. Weaver, the beds 

 pass downwards into the Ludlow rocks.- There appears, how- 

 ever, to be evidence of overlap of the upper beds of Old Red 

 Sandstone on to the Llandovery rocks. The Lower Old Red 

 Sandstone and Ludlow beds are also conformable in the neigh- 

 bourhood of Rhymney, near CardilT.^ 



In the Cheviot District, resting unconformably on the Silurian 

 rocks, there is a great series of felspathic tuffs, ashy grits, and 

 lavas (porphyrites), together with chocolate-coloured sand- 

 stones and conglomerates, which constitute the Cheviot Series, 

 and may be grouped with the Lower Old Red Sandstone. The 

 eruptive rocks (which are from 1500 to 2000 feet thick) form 

 the highest points in the Cheviot Hills, which extend from the 

 head of the Tyne in Northumberland and of the Liddel in Rox- 

 burghshire, to Yeavering Bell, near Wooler, in Northumberland, a 

 distance of thirty miles. Of these heights Cheviot itself is a broad- 

 topped hill, 2767 feet above sea-level. The Cheviot Series is 

 much denuded, and overlaid unconformably by conglomerates 

 and sandstones belonging to the Upper Old Red Sandstone. 

 (See Fig. 16.) Prof. James Geikie has stated that the chief focus 

 of eruption was near Cheviot, and that the volcanic deposits were 

 mostly subaqueous.* 



Economic products, etc. 



The Cornstone beds, which occur extensively between Monmouth and Aber- 

 gavenny, were in former days extensively burnt for lime. The beds have also 

 been worked at Credenhill near Hereford. 



Many of the sandstones are used for building-purposes, and these, as well as the 

 cornstones, are sometimes used for mending roads. Some beds known as ' fire- 

 stones ' have been employed for making hearths. The sandstone is sometimes 

 known as the Hereford Sandstone, and the Three Elms Stone, near that city, 

 has been much quarried for building purposes. The sandstone is also quarried 

 near Ledbury and Malvern. The Cradley sandstones have been largely employed 

 at Malvern for building-purposes. 



The Old Red Sandstone yields in places a strong loamy soil, which is fertile and 

 largely devoted to pasture : many orchards are situated upon it, and a few hop- 

 yards. In some places, however, the soil is wet and boggy, and consequently 

 unproductive. The Cornstones form the richest land in Herefordshire. 



^ Records of the Rocks, p. 234. 



2 T. G. S. (2), i.317. 



3 W. J. Sollas, Q. J. XXXV. 488. 



^ The Cheviot Hills, by J. Geikie, Good Words, 1876. 



