224 



THE GEOLOGIST. 



boniferous limestone is seen to dip conformably to, and rest upon, these 

 very strata. Mucli of the picturesque scenery of the road from Boss 

 past Penyard Castle to Hope lEansell is due to highly inclined strata, 

 forming headlands of these upper beds, the average mean dip of which, 

 however, is not more than 25^ towards the coal-field. As a rule, 

 fossils are very rare, excepting in one seam of blue argillaceous shale, 

 about the middle of the series, and a bed of coarse-grained yellowish 

 sandstone near the top, where the remains of plants are tolerably 

 numerous ; there are also some impressions of shells in a thin bed of 

 sandstone, about a foot in thickness, which immediately subtends the 

 limestone-group. 



These upper beds rest upon the conglomerate -beds, which make up a 

 thickness of some 200 feet or more of coarse-grained sandstone, much 

 charged witli per-oxide of iron, and containing dispersed quartz and 

 other pebbles, marl-partings, and thin bands of small pebbles, the 

 whole iuterstratified in irregular, lenticular-shaped drifts, affording 

 lozenge and diarfi.ond-shaped sections, several of which may be seen 

 on the road across the Wye Yalley, from "Wilton to Eoss. Many other 

 sections, equally characteristic, are to be obtained between Ross and 

 3Ionmouth. 



The high grounds round the Monmouthshire side of the Forest abound 

 with gigantic blocks and solitary tors, composed of the conglomerate, 

 which forms the outlier known as the Buck-stone," which is usually 

 mistaken for, and mis-stated to be, a Druidical monument, besides 

 having a host of other mythic legends and stories connected with its 

 suppositious history. 



The cornstones, and some members of the Old Eed Sandstone, call for 

 no notice in this place, since I have merely introduced the description, 

 already given, of the superior beds of Old Eed, from the circumstance of 

 that deposit forming the base, as it were, of the basin, and, in conjunction 

 with the account, next following, of the Carboniferous limestone and of 

 the Coal-measures, making a connected sketch of the general geology 

 of the district. 



II. Caebonifehous Liaiestoxe. 



The Carboniferous limestone would mark a continuous band round 

 the Forest of Dean, flanking and underlying the Coal-measures, but 

 that it is cut off on the south-east by a down-throw fault, commencing 



