656 C. CALLAWAY ON A NEW AREA OF UPPER 



Jones, Orthis testudinaria, Dalm., Theca, several species of Lamel- 

 libranchs, Diplograpsus jpristis, His., and Favosites Jibrosus, Goldf. 

 Overlying the Harnage Shales, and forming a ridge parallel to the 

 ridge of the Hoar-Edge Grits, is the Chatwall Sandstone with 

 Orthis alternately Sow. 



The May-Hill Sandstone laps round the whole of the older forma- 

 tions from the Shineton Shales to the Chatwall Sandstones, and is 

 clearly unconformable to all, the dip being in every case I have 

 observed lower than the dip of the beds on which it rests. 



It will be seen from the above facts that the Hoar-Edge Grits, the 

 Harnage Shales, and the Chatwall Sandstone, all thin out very near 

 together in the area between Stonehouse and Broomcroft, the three 

 subformations succeeding each other in regular order without dis- 

 turbance beyond their elevation at an angle. 



Lower Caradoc Rocks in the Cound-Harnage district. — North of 

 the Shade well- Coppice ridge, the Hoar-Edge Grits and the Harnage 

 Shales assume characters which are stratigraphically discordant 

 with their relations in the area just described. This discordance is 

 apparently caused by the well-known fault which runs from the 

 Wrekin many miles to the south-west, and in the Harnage district- 

 brings the Carboniferous, Permian, and Triassic rocks down against 

 the Caradoc. These lower Caradoc strata cover an area of nearly three 

 miles, from the river Severn on the north-east to Acton-Burn ell 

 Park below Shadewell Coppice on the south-west, and | mile 

 in their greatest breadth. They are well exposed on Cound Brook 

 where it runs through Evenwood Common, and on the same stream 

 and its easterly branch in the picturesque dells to the south-west of 

 Harnage. The strike of the Harnage Shale is, roughly, north-east, 

 sometimes ranging round to east-north-east. The beds are sometimes 

 nearly vertical ; but more frequently they dip at a high angle to the 

 south-east or to the north-west, the north-westerly dips in some cases 

 being as low as 45°. These shales are often very fossiliferous, contain- 

 ing the fauna above described. They are moderately fissile, but less 

 so than the Shineton Shales, of a blue colour, changing to olive near 

 the surface, and often marked with iron-stains, these changes being 

 obviously due to peroxidation of the ferrous oxide. 



With the Harnage Shales are associated the Hoar-Edge Grits, 

 which, as in the undisturbed areas, consist of coarse sandstones, 

 sometimes forming conglomerates, and containing a bastard limestone 

 arising from the abundance of fossils. It is not necessary to my 

 present purpose that I should describe these rocks in detail ; suffice 

 it to say that, in the dells near Harnage, the Lower Caradoc strata 

 form hills consisting of outliers of low-dipping or horizontal Hoar- 

 Edge Grit resting upon the upturned edges of the Harnage Shales, 

 the older lying unconformable 7 upon the younger. At Acton Pigott, 

 to the south-west, the sandstone constitutes an outlier nearly a 

 mile in length. A portion of this outlier forms a cornice over- 

 hanging Cound Brook at Evenwood Common, the lower portion of 

 the banks of the stream consisting of the nearly vertical Harnage 

 Shales. The extraordinary relations of these subformations at 



