24 BLACK MOUNTAIN DISTRICT. 



tures In geology which it is impossible to condense, and the student 

 must make up his mind, if he would understand them, to become 

 thoroughly acquainted with the phenomena themselves. In notes 

 necessarily so brief as these, we can do nothing but give a few hints 

 respecting the most striking of the wonders presented to our investi- 

 gation, and then ask the geologist to pass onwards and to observe, 

 record, and theorise for himself. 



The geological history of the Black Mountain district cannot be 

 described, it must be studied. I can but reiterate here what I have 

 endeavoured to impress, at greater length, in another treatise,* state- 

 ments of which the proofs are difficult to express in words, but of 

 the truth of which I am firmly convinced. 



The strata on the summit of the Black Mountain are the beds of 

 the Upper Old Eed Sandstone. These strata formerly extended far 

 over the highest Cornstone hills of Herefordshire ; over the Silurian 

 rocks of Kington ; over the vales to the distant Glees and Malvern ; 

 over Dean Forest and the Severn at Tortworth. 



The outliers of the South Wales Coalfield, the Carboniferous rocks 

 at the Forest of Dean, Pen-cerrig Calch, the Clees, reveal that over 

 a great portion of this Upper Old Eed district, the Carboniferous 

 rocks must have been deposited, and the physical geologist who 

 stands upon the summit of the Gadir Vaior, that point of the Black 

 Mountain that rises high above Talgarth, and stands out a monumental 

 witness of the wonders of geology, knows that even above that 

 mouttain peak there was once piled a mass of sedimentary deposits, 

 themselves formerly the bed of an ocean. 



At Cusop, near Hay, the grey Sandstones that overlie the Corn- 

 stones are quarried for building stone. They contain remains of 

 plants, and the equivalent rocks, near Kentchurch, at the summit of 

 Eowlstone hills, have furnished the only fossil, a Stylonurus, that has 

 been hitherto discovered in beds so high up in the Old Eed rocks of 

 Herefordshire, with the exception of the Upper yellow sandstones 

 of Farlow, in which Mr. G. Egberts and Mr. Baxter, of "Worcester, 

 detected the remains of Pterichthys and Holoptychius. I mention 

 these Farlow Sandstones as I perceive that Farlow is an outlying 

 portion of Herefordshire. 



• " Old Stones." 



