TOLCANIC EOCKS OF DAETMOOK. 



289 



Fig. 1. — Flan of the Brent-Tor Basin, showing the Faults and the 

 lines of the folloiuing Sections. 



W. E. 



are thrown into long anticlinal and synclinal folds. On the west a 

 small and nearly triangular area includes all that remains of the 

 Brent-Tor volcanic series in this direction. To the south it is 

 possible, as suggested in this paper, that the schistose beds about 

 Saltash, ten or twelve miles distant, may belong to this volcanic 

 series. 



The first section which I have taken to illustrate the relations of 

 the beds is one running IST.jN'.W. across Eam's Down (fig. 2). It 



Fig. 2. — Section (1) across Hani's Doivn. 



N.N.W. S.S.E. 



Milton 

 Eam's Down. Abbot. Combe. Twowell. 



lies on the west of our typical basin. Here two beds of the volcanic 

 series are seen, the older marked with the letter c, the younger with 

 d. As they undulate, and their crests have been denuded, there are 

 three separate exposures of the bed c, flanked on either side by the 

 bed d. In speaking of these exposures as beds, it should be under- 

 stood that they commonly consist of a series of beds (lavas, tnffs, &c.). 

 The next section (fig. 3) runs in a S.S.E. direction, from Littonary 

 Down, across IIeathfield,to Tavistock. From Meather to Churlhanger 

 we see a synclinal disposition of the beds, which dip northwards to- 

 wards Lower Chillaton and Quether, while on the south the bed c 

 is repeated by several undulations, and is then succeeded south of 

 Tavistock by what I believe to be two older lava-flows, lettered re- 

 spectively a and h. These four series of beds a, 6, c, and d represent, 

 so far as I can ascertain, the whole of the Brent-Tor volcanic series 

 subjacent to the stack of lavas and agglomerates which constitute 

 the tor itself. 



