372 W. A. E. TJSSHEK ON THE TEIASSIC 



" There is a large development of this conglomerate at Stratton- 

 on-the-Fosse, where it comes in contact with the exposed edges of 

 the Coal-measures, and again at Mells, whence a narrow belt passes 

 beyond the village of Elm, skirting the limestones to Yallis. Con- 

 glomerates are also found continuously along the limestone escarp- 

 ments, filling up the inequalities of the surface on both the north 

 and south flanks of the southern portion of the Mendips. . . . Pew if 

 any organic remains of a locality so disturbed as were the probably 

 local coast lines on which these pebbly deposits were laid down can 

 be expected to have been preserved." (Moore, "Abnormal Secondary 

 Deposits," I. c. p. 455.) 



Mr. Moore says the dolomitic conglomerate is found to vary 

 from 3 to 60 feet in thickness. 



Mr. Moore (" Abnormal Secondary Deposits," I. c. p. 498) gives the 

 following representation of the Trias in the Mangotsfield railway- 

 cutting : — 



Under Blicetlc Beds. 



Keuper, consisting of variegated red and blue marls with sul- "■ in ' 

 phate of strontia, passing into regularly bedded New Eed 

 Sandstones without organisms about 25 



Hesting on Pennant Rode. 



In the same paper (ibid. p. 458) he says : — " It will be seen that 

 within this part of the Somersetshire coal-basin the Triassic rocks 

 are reduced to a little over 50 feet, whilst south of the Mendips, 

 and where only partially proved, they attain a thickness of G09 feet." 



He says further (p. 476), " Comparing the greatest thickness 

 ' of the Trias ' without the coal-basin with the greatest reduction 

 above the coal-measures within it, we arrive at the following- 

 remarkable result." 



Without the Coal-basin. Within the Coal-basin. 

 ft. in. ft. in. 



Triassic beds .. 2000 50 



Mr. Moore gives the thickness of the Trias at the Tyning Pit 

 (near Radstock) as 186 feet, of which 19 feet at the base consist 

 of dolomitic conglomerate. 



At Norton-Hill Pit the marls are given as 118, and the con- 

 glomerates 54 feet in thickness. 



At Eatheaston a pit, in 1812, showed 54 feet of Trias under 

 Bhastic beds. 



The red marls of the northern area were deposited continuously 

 with the upper portions of the marls, upon which the Blackdown 

 greensands to a great extent rest directly. 



The same general description is applicable to the latest stage of 

 deposition in the three districts under consideration ; but the great 

 attenuation exhibited by the Trias of the northern district precludes 

 any attempt at correlation as regards time with the much greater 

 development of marls which in South Devon form only the upper part 

 of the Trias." 



As we have no reason for inferring that deposition was more 



