Geology of the South-east of Devonshire. 



451 



deposit ranges over the summits of the hills above Coffinswell, passes into the valley a little below Kings- 

 kerswell, and then rises into the opposite hills ; near Aller Mills it contains beds of yellow ochre, with 

 sand and light-coloured clay — an association very like that at Shotover ; and it crowns the hills above 

 Woolborough. On the other side of Newton it forms very compact beds a little beyond White Hill, 

 beneath clay and debris, and also at Ringslade. From Staple Hill (fig. 2.) to the Ashburton road the 

 greensand acquires considerable breadth, the strata dip at a high angle, and appear broken : intermediate 

 between the greensand and the " head " are the white beds, which may perhaps represent chalk. 



The TrigonicB which occur in the arenaceous beds at Staple Hill, prove the 

 deposit to belong without any doubt to the greensand. 



Crossing over to the opposite side of the valley, similar beds are well exposed by 

 Bellamarsh. On each side of the road leading down to Combe Farm, we have 

 an artificial section, fig. 6, showing the base of the deposit, resting on carbona- 

 ceous shales, and containing fragments of culmiferous grit, also Exogyrse, Pecten 

 quinqueco status, &c. in great abundance. 



Fig. 6. 



Greensand. 



Carbonaceous 

 Shales. 



Greensand resting on Carbonaceous Shale, near Combe Farm. 



Below Ponswine Farm the formation presents fine-grained beds with green earth 

 and numerous characteristic fossils. The deep cutting for the new road affords a 

 good section, showing the thick capping of debris resting on the furrowed surface 

 of the greensand : in this section are lines of chert, and some very remarkable beds 

 almost entirely composed of Orbitolites. 



The greensand along all this course occupies the slopes of the hills which form 

 the Bovey valley, and it rests on new red, carbonaceous, and transition strata, 

 perhaps upon granite, as near Letford Bridge, on the road to Lustleigh. 



Pipeclay occurs towards the base of the greensand in Great and Little Haldon *, and attempts have been 

 made to work it near the western extremity of Great Haldon. In a deep water-course below Wool- 

 borough, pipeclay beds alternate with sand, and an alteration of the road near Ford presented an inter- 

 esting section of similar clay -beds alternating with greensand. 



A small outlying patch of greensand occurs near Larcombe Bridge, below Ide- 

 ford, a connecting link between the Haldon deposits and those of the Bovey valley. 



* It is the bed in the section presented by a well, carried through the entire thickness of the deposit 

 by Sir Robert Newman, quoted by Mr. De la Beche, Report, p. 247. 



