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XXXIX. A Geological Description of the Neighlotirhood of 

 Bristol. By W. H, Gilby^ Esq. 



To Mr. TiUoch. 



SfU, — X HE paper which I have ventured to transmit to you, 

 contains a geological description of the neighI:)ourhood of Bristol. 

 Some time after I had commenced my inquiries, I saw for the 

 first time Mr. Tovvnsend's very valuable book " On the Charac- 

 ter of Moses established for Veracity as an Historian," wherein 

 I found interspersed throughout the body of the work much im- 

 portant information respecting the structure of this quarter. 

 Admirable as his descriptions are, it appeared to me that some 

 interesting particulars, having perhaps no immediate relation to 

 his conclusions, remained yet to be detailed. In the paper that 

 I have addressed to you, I have endeavoured to supply those 

 particulars, and to give, a more connected account of the forma- 

 tions in tliis quarter ; and should it appear to you to be worthy 

 ©f a place in your Journal, you will oblige me by inserting it. 

 I am. 



Very respectfully yours, 



York Crescent, Clifton, Bristol, W. H. GiLBY. 



September 'U, 1814. 



The rocks in this quarter may be divided Into those that arc 

 inclined, and those that lie unconformably ia a horizontal posi- 

 tion upon the tops of the inclined strata. In the following de- 

 scription I shall hrst speak of the inclined strata, and l)egin with 

 the limestone and its accompanying formations, wliich range 

 round the country somewhat in an elliptical form. I shall theit 

 speak of the coal-measures which this ellipsis incloses. The 

 horizontal strata will then be treated of; and I shall, lastly, enu- 

 merate those minerals which occur partially, or in veins, in the 

 preceding formations. 



The rock which forms the most prominent feature in this 

 quarter, and gives rise to all the bold and picturesque scenery 

 which many jjarts of tiiij} country are remarkable for, is the gray, 

 compact, mountain limestone. Mr. Townsend hais very accu- 

 rately described the diiferent localities of this rock. It ranges 

 round Bristol in almost every direction, and forms, in fact, an 

 irregular kind of basin, of which the most northern points are 

 the hills about Thurnl)ury. On the east it is well observed in a 

 continuous range at Wickwar and Sodbury ; and in a very bold 

 jnauner at Week, about half way on the upj)er road to Bath 



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