Border Country of Salop and North Wales ; ^c. 239 



appears not a little curious and interesting*. The softness of the shale in 

 which they are imbedded, also contributes to render these specimens of fossil 

 shells remarkably perfect, the muscular impressions and interior structure of 

 the larger terebratulae being exhibited with great distinctness. 



The valley situated between the Craigs of Eglw-y-seg and the Oernant 

 Mountain, contains hills of moderate elevation. Their superior fertility and 

 beauty, the lively red colour of the ploughed fields, and the rounded masses 

 of red conglomerate scattered among the debris of the limestone, prepare the 

 geological traveller to expect a rock such as that of which they consist, and 

 which is hard, highly ferruginous, stratified, tending to slaty, and composed 

 of grains and small pebbles of the older rocks united by an argillaceous 

 cement. This rock is therefore a variety of the grauwacke of the continental 

 geologists. Its extent is very limited. Nearer Llangollen and about the steep 

 hill of Dinas Bran, we find only the common appearances of the beds of shale, 

 slate, and slaty sandstone, about to be described as occupying by far the 

 greater part of the region under our review *. 



2. The next section which I shall attempt to describe, is represented by a 

 line drawn from Oswestry westward to Llansilin. Such a line crosses, within 

 the space of 5 miles, the basset edges of all the strata from the new red sand- 

 stone to the slate. 



After quitting the level ground about Oswestry, which consists of gravel, 

 clay, and sand, and covers beds of coal, we come to the strata which dip 

 under the coal, and belong to the millstone grit formation. These strata 

 form several successive ridges^ which rise higher and higher as we advance 

 towards the west. The eastern slope of each ridge appears to correspond 

 with considerable exactness to the plane of the strata beneath it, although 

 these strata are overspread with gravel, clay, and sand. The western slope 

 is steeper, cutting across the outcrop of the strata. On the summit of one 

 of these ridges, at the distance of 2 miles from Oswestry, is the race-course, 

 commanding an extensive view of the rounded slate mountains of Wales on 

 the west, and of the plain of Shropshire to the east. Besides the Wrekin 

 and the other hills, which encompass this plain to the south and east, another 



* It may here be remarked, that at the entrance of the Vale of Llangollen the rocks on each 

 side are limestone, and that the lower beds are bituminous, and highly fetid when rubbed or 

 struck. They contain shells of the Productus Scoticus of Sowerby, (tab. 69. fig. 3.) which he 

 had received from the limestone of the great coal formation in Scotland, and which was found also 

 by Mr. Henslowinthe Isle of Man.(Geol.Trans.vol.v. p 493,) Their stratification is exceedingly 

 regular, the beds being about 8 inches in thickness. 

 VOL. II. SECOND SERIES. 2 I 



