1863.] SALTER UPPER OLD RED SANDSTONE. 485 



Further north, in the midst of the undulating trough of Culm- 

 measures, a locality called Yealm Bridge, north of Launceston, has 

 long been known as a fossiliferous place. It is a sharp and faulted 

 anticlinal of hard slate-rocks, about a mile or a mile and a half in 

 diameter ; and Mr. Pattison, who knows the spot well, told me I 

 should find Petraia and Phacojps latifrons there. This then would 

 identify the rock with the Barnstaple series, of which we otherwise 

 have no trace on the south edge of the Culm district. I found this 

 statement strictly correct; and the list of fossils, imperfect as it 

 must be (being the result of only two days' examination), is yet a 

 sufficient index of the true geological position. The dip being north- 

 wards, and the Culm unconformable, it was only to be expected that 

 we should find higher beds in an exposure to the northward ; and I 

 believe this small inlier (to adopt a new and proper phrase, invented 

 by Mr. Drew) is one of the best proofs we could have that the 

 Barnstaple or Pilton group overlies the Petherwin group. 



§ 4. Somersetshire, Gloucestershire, and Shropshire. 



Before passing over to the South of Ireland, it will be well to 

 notice the general character of the parallel sections further to the 

 north-east, namely, at Dean Forest, Bristol, and the Mendips ; and 

 to call attention to the newly described section of the Clee Hills, as 

 given in Mr. Roberts's and Professor Morris's account in the Society's 

 Journal*. This must necessarily be brief, and it may be at once 

 stated that all these sections conform nearly to the northern type, 

 or that of Tenby above described. In all, the thick limestones are 

 succeeded, in the downward section, by arenaceous shales and thin 

 limestone-beds, and these by sandy beds, grey, and finally yellow as 

 they pass into the red marls and sandstones of the Upper Old Red. 



In Dean Forest Mr. James gives f, below the alternating shale- 

 series, the following beds : — 

 p , -r. f Arenaceous shales. 



\ Coarse yellow sandstone containing Shells. 



f Red marl. 

 Red marl with yellow sandstone. 

 Coarse yellow sandstone and whitish shale, full of 

 Upper Old Red.<; Plants. 



Green shale and sandstone. 



Red marl. 



Thick yellow sandstone, with whitish shale. 



Red marl. 



Greenish and grey sandstones and shale, very 

 micaceous, <fcc. 



And so on until the whitish and grey sandstones cease to appear 

 among the red marls. We must, by comparison with the Tenby 

 sections, draw the divisional line as above. 



In the Lower Purlieu section, in the same district, the limestones, 



* Vol. xriii. p. 94. f Greol. Surv., Vertical Section No. 12. 



