8 PROCEEDINGS OF THE COTTESWOLD CLUB 



are situated, a fact which means that the valle}' has been 

 • lecpened to this extent since the gravel was deposited. 



The drive was then continued to the foot of Frocester 

 Hill. There the members left the break, and, under the 

 guidance of Mr S. S. Buckman, examined the geology. 

 Attention was first drawn to a roadside section, showing 

 beds yielcHng Ammonites bifrons and A. falcifer, species 

 characteristic of the Upper Lias. 



The geological structure of the hill was then explained : 

 a short distance up the hill is the Marlstone, a hard rock 

 of the Middle Lias, which generally forms a particular 

 feature of the Cottcswold landscape as a lower subsidiary 

 escarpment of the hill flank, projecting beyond the more 

 lofty escarpment of the Oolitic rocks. Above this is a 

 considerable thickness of clay beds — the Upper Lias upon 

 which the members were standing : and they are of 

 economical imj)ortance as l)eing one of the water-bearing 

 l)eds of the district. The clay is capped by an immense 

 development of the Cotteswold Sands — in the present 

 case nearly 250 feet thick, as ascertained l)y measurement 

 with the level, and these are covered by iron-shot, 

 calcareous, marly strata, surmounted bv some Oolitic 

 rocks. By means of a coloured diagram showing sections 

 of various localities between Frocester Hill and the coast 

 of Dorset, Mr Buckman explained both here, and when 

 the party arrived at the top of the hill, the result of his 

 work during the last ten vears, namely, that the sands of 

 the Cotteswold Hills, over which there had been .so much 

 controversy, as the annals of the Club can testify, were 

 not deposited contemporaneously with the sands of Bath 

 and Dorset, though they are similar in colour and appear- 

 ance. The fact is, he said, that the sands of the 

 Cotteswolds had all been deposited, and part of the 

 over-lying cephalopod bed had been laid down, long before 

 sands began to form in Dorset ; and that the underlying 

 clav beds in Dorset which have always, on account of 



