8b PROCEEMJS^GS OP THE GEOLOGICAL SOCIETY. 



bright-green grains, both of which are fossiliferous, and partly of 

 olive-colonred sHghtly micaceous and rather massive sandstone, in 

 which no fossils have yet been detected, and which is well seen in 

 an old qnarry at the base of the northern extremity of the Eagged- 

 stone Hill, near the turnpike-road ; but the exact order of superposi- 

 tion among the different beds is not determinable for want of more 

 numerous exposures. Above the volcanic rocks are greenish sand- 

 stones containing SerpuJites, and overlying these are thicker beds 

 abounding in Trachyderma antiquissima , Salt. 



Of the lava-beds, two of them constitute hillocks on the south-west 

 side of Midsummer Hill, in one of which, nearest to the road, a small 

 quarry has been opened. The rock consists of an intimate mixture 

 of felspar and augite, and is of a brownish or reddish-brown colour, 

 uncrystallized, and has occasionally small specks of augite *(?) 

 disseminated through it. A larger but similar bed of lava occurs on 

 the western slope of the Kagged-stone Hill. The northern extremity 

 of this bed was cut through in making the turnpike -road, and it 

 extends southwards from the road nearly three-eighths of a mile. 

 Part of it on the hill-side is nearly black, and almost entirely augitic ; 

 but the greater portion of it is a brownish and reddish-brown 

 felspathico- augitic rock similar to the other twof . Further to the 

 south, in the VaUey of the White-leaved Oak, and abutting against 

 the metamorphic rocks of the north-eastern extremity of the Keys 

 End Hill, there is a fourth lava-bed interstratified with the sand- 

 stones, which differs from the former in its darker colour, owing to 

 the larger proportion of augite it contains, and in having some im- 

 perfectly formed crystals of hornblende sparingly scattered through 

 its substance. 



In the quarry at the southern extremity of the Eagged-stone Hill, 

 previously alluded to when speaking of the metamorphic rocks, these 



Fig. 2. — Shetcli sliowing tlie Junction of the Hollyhush Sandstone with 

 the Metamorphic rocJcs as exhibited at Ragged-stone HiU%. 



* Or hornblende. 



t " Felspathic trap," Phillips (op. cit. p. 52). 



X By J. W. Salter, Esq., F.G.S. 



