127 



There are, moreover, certain beds exposed in a lane-cutting west 

 of East Brent Church, that were described by my colleague, Mr. 

 W. A. E. Ussher, as " hard and rather fine-grained light grey 

 Limestone, with bluish-grey spots, containing Ammonites." These 

 beds are interstratified with clay, and I formerly regarded them 

 as Lower Lias,* but they proved on re-examination to contain 

 Ammonites communis, and thus to belong to the Upper Lias. 

 This additional evidence confirms the view that no Lower Lias is 

 exposed at Brent Knoll. 



The upper sandy beds of the Middle Lias are not well exposed 

 in this hill, but they form a comparatively steep scarp, surmounted 

 by the Upper Lias. Nor are the Midford Sands shown in 

 section, although portions of the beds are thrown out from many 

 rabbit burrows. The thin capping of the so-called " Cephalopoda- 

 bed," that had been inferred from the rubble and loose blocks 

 of calcareous sandstone of which the walls of the Camp are 

 formed was again examined and I was fortunate in finding a 

 specimen of Rhynchonella cynocephala in one of the small 

 exposures, in re-arranged material on the summit of the Knoll. 

 Another and fragmentary specimen was also obtained from a 

 loose block of calcareous sandstone by Mr. J, E. Clarke. 

 Considering the nature of the ground, this is the most 

 satisfactory evidence that could be obtained of the age of the 

 beds forming the Knoll. Specimens of Serpvla also occurred, 

 and these prevail at the same horizon below the Inferior Oolite 

 in the neighbourhood of Beaminster and Crewkerne. 



It should, however, be mentioned that a variety of Rhynchonella 

 cynocephala has been found by Mr. E. Witchell in the lower beds 

 of the Inferior Oolite near Stroud,t so that the species has a 

 higher range in the Cotteswold district than it is known to have 

 in Dorsetshire. 



* " Geology of East Som«rset," &c., p. 116. 

 t " Geo.'ogy of Stroud," 1882, p. 47. 



