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Notes on the Geokxjij of Brent Knoll, in Somersetshire. By 

 Horace B. Woodward, F.G.S.,* of the Geological 

 Survey of England and Wales. 



(Read March 10th, 1886.) 



The conspicuous hill of Brent Knoll rises to a height of about 

 450 feet above the Alluvium of the Burnham Level between 

 Highbridge and the ]\Iendip Hills j its precise height above the 

 sea-level is 457 feet. Some attention has been given to its 

 Geological structure, but as it has been differently interpreted, 

 a few remarks on the subject may be of interest. Thus the area 

 occupied by the Romano-British Camp, was regtirded by Conybeare 

 and also by William Sanders as Inferior Oolite,t while on the 

 Geological Survey Map (sheet 20) it was originally coloured as 

 Marlstone or Middle Lias, the lower portions of the hill being 

 regarded as Lower Lias, During the re-survey of the district in 

 1872, it fell to my lot to examine Brent Knoll, and in the 

 Memoir subsequently published, a section to illustrate the 

 structure of the hill was inserted. J This section represented the 

 Knoll to be capped by a thin layer of the "Cephalopoda-bed" 

 (below the Inferior Oolite), together with other portions of the 

 Midfoi'd or Inferior Oolite Sands ; and to be based on a platform 

 composed of Upper, Middle, and Lower Lias. 



No natural section was to be seen at the encampment, but 

 there were loose blocks of sandy and ferruginous limestone which 

 contained Ammonites; and although too imperfect for specific 

 determination, the specimens were considered by Mr. Etheridge 

 to belong to a tj'pe that characterizes the so-called " Cephalopoda- 



* This papei' is communicated by permission of the Director General 

 of the Geological Survey. 



t Conybeare and Phillips' " Outlines of the Geology of England and 

 "Wales," pp. 255, 275 ; Sanders' " Map of the Bristol Coal Fields," 1862. 

 X "Geology of East Somerset," &c. (Geol. Survey), p. 116. 



Vol. 6, No. 2. 



