8 



clevatioQ and denudation ; the actual thickness of strata, in relation 

 both to the horizontal aud vertical lines drawn through them;* 

 deceptive appearances, of frequent occurrence pointed out, arising 

 from faults, repeated strata and strata rolled over. Remarks wero 

 made on the sedimentary and mineral structure of rocks, the creation 

 of organic beings, their duraion and extinction, and the importance of 

 their imbedded remains in the identification of coteniporary deposits. 

 Several of the most remarkable fossils were collected. I need not 

 trouble you with their well-known names. It is an advantage of 

 our field days, that they must send us to our b )oks ; whereas, owing 

 to the vis inerttce of our nature, the perusal of the very best books on 

 the subject will not necessarily send us into the field : for this 

 reason, most strictly one of bodily and mental enjoyment, such 

 clubs as ours are worthy of all encouragement. Our walk was con- 

 tinued over Croft Ambrey and along the escarpment of Yatton Hill, 

 which aflTord most extensive and instructive views of the old red 

 sandstone and Silurian districts, from the Cambrian ranges f>f North 

 \V?les, beyond the Cornden and Stiper stones to the b.-isaltic top of 

 the Clee Hills, Abberley, the Lickey, Malvern, Woolhope, May 

 Hill, the Cotteswold, Forest of Dean, and South Wales. A grand 

 physical feature, hereafter alluded to, the repetition of the upper 

 Silurian rocks, exterior to the south side of the Wigmore valley of 

 elevation, in a great bow, commencing near Aymestry, and extend- 

 ing to the Ambrey and the Palmer's Cairn, in the parish of Orleton, 

 was pointed out. In our descent to Aymestry we took tlie path of an 

 old road, up which I had the honour of conducting Mr. Murchison 

 (now Sir Roderick); in his first visit to Herefordshire, July, IS31, 

 presenting in itself a continuous section from the lower Ludlow rock 

 to the old red sandstone. I had at this time very fairly developed 

 the structure of the surrounding country. My own researches in 

 this district commenced with my residence, at Aymestry, in 

 1827: but I was working in the dark, and it was in that walk, 

 which I continue to regard as one of the most interesting events of 

 my life, there dawned upon me the vision of the deep interest of the 



• The thickness of any strattim in relation to a ■horizontal line drawn through 

 it, is ;= that line multiplied by the natural sine of the angle of iQclination of 

 stratum ; and in reference to a vertical line, is = the vertical line multiplied by 

 the natural co.sine of the same angle of inclination. 



