2i8 Geology.. 



ous Limestone and the old Red Sandstone, even mounting 

 up to the summit of the hills. It is made up of the 

 debris of the rocks on which it rests, including pebbles from 

 the Old Red Sandstone and hollow nodules called " Potato 

 Stones," lined with crystals of quartz and calc spar, Millstone 

 Grit and Mountain Limestone, cemented together by carbon- 

 ate of lime and maghesia ; — hence its name, Dolomitic Con- 

 glomerate. Mr. Etheridge-has called it the "Palaeozoic beach 

 of the Period," skirting the land at the time of its deposit, and 

 rising higher and higher up its flanks as depression went on. 

 It persistently occurs throughout the district, rarely more than 

 30 feet thick, and bears witness to that enormous erosion 

 described so graphically by Prof. Ramsay ; for when asked 

 where all that mass of strata has gone to which is supposed 

 once to have arched over the Mendips, the geologist points to 

 this " old beach " and says " si quseris monumentum circum- 

 spice." A very fine section of this formation may be seen on 

 the Bath and Evercreech line, between Midsummer Norton 

 and Chilcompton ; at Yate, too, and near Doynton, if the yellow 

 Conglomerate there found similar to that at Clevedon be 

 identical. Various opinions have been held as to the exact 

 age of this Conglomerate, but by general consensus it may 

 be now put down as indicating the coming in of the Keuper 

 Sandstones and Marls ; that formation which attains so great 

 a thickness in the Midland Counties, and as Horace B. 

 Woodward {Memoir, Geol. Surv., 1876) writes, "maintains 

 the same relation to the Keuper Marl as the pebble 

 beaches of the present day do to the sands associated with 

 them." 



Kquper Marls Covering this pebble bed, and dovetailing 



and with it, come the Red Sandstones and Keuper 



Sandstones. ^^ Poikilitic Maris, red, grey, and green in 



