1868.] nOLL SOUTH DPJVON and east CORNWALL. 437 



the grits of Knighton, must cnrve round to the south-east ; but if they 

 do so, the dips in the argillaceous rocks of Down Thomas and Longdou 

 must be deceptive. The red grits of Staddon Point are much folded, 

 and some of the beds inverted, but the general dip is southerly ; and 

 above them are the grey and bluish slates, with thin grey grits, of 

 Bovey Sand Bay ; and these are succeeded by reddish slates, ])artly 

 argillaceous and partly hard and micaceous, like those of Kings- 

 wear. The general appearance of these rocks along the shore of 

 Plymouth Sound reminds one of the section on the Dart river. 



These rocks are continued across Plymouth Sound without any 

 material variation. The argillaceous slates which overlie the lime- 

 stone at Mount Edgecombe correspond to those of Jenny Cliff Bay, 

 but west of Millbrook they become interstratified with bands of grit, 

 lied arenaceous rocks like those of Staddon Point succeed these at 

 Marker Church, and are continued southward as far as the Barracks, 

 where a mass of reddish felspathic rock * separates these grits from 

 the grey slates of Kingsand and Cawsand. This mass of igneous 

 rock appears to have carried the grits somewhat to the north of the 

 general line of strike ; but the latter are not continued across the 

 promontory to Whitesand Bay in exactly the same mineral condition, 

 their place on the coast being occupied by coarse slates with thin 

 grit-bands. The rocks of Kingsand and Cawsand are similar to 

 those of Bovey Sand Bay ; and similar rocks, sometimes reddened, 

 are continued to Penlee Point and the Rame Head. The dips 

 are all southerly, at angles varying from 35° to 45° or more. 



Returning to the Kingsbridge promontory, we find coarse reddish 

 slightly micaceous slates, similar to those of Kingswear, extending all 

 along the shores of Start Bay, from the mouth of the Dart to Slapton 

 Bridge, dipping southerly at angles varying from 30° to 60° or 

 more. On the west, on the other hand, soft argillaceous grey, 

 blue, or purple slates occupy the whole of the distance between Ave- 

 ton GiiFard and the metamorphic rocks at Hope. At Aveton Giffard 

 there are some blue and green evenly laminated slates, the laminae 

 of which dip S. 20° E. at 70° or 80° ; and to the south of these 

 a long belt of argillaceous rocks, apparently an anticlinal axis, which 

 includes a band of similar roofing- slates, ranges about N". 10° E. from 

 the coast between Rigmore and the mouth of the Avon, past Church- 

 stow, to Buckland Tout- Saints and Nethertou, and thence towards 

 Coles Cross and Heathfield. In an opposite direction coarse reddish 

 slates, mingled with others that are more argillaceous, but for the 

 most part red, trend westward from the north of Slapton by Hart- 

 ston, to the grit beds of Marlston, north of Sherford, and thence to 

 Kingsbridge. AU these beds dip to the south at high angles ; but 

 along a line extending from Hurleston by the north of Charleton and 

 Stokenham to Slapton Sands the dip becomes reversed, and the beds 

 rise to the south ; and with them a band of dark bluish-grey roof- 

 ing-slate, similar to that of Buckland Tout- Saints, and Netherton, 

 which crops out along a parallel line crossing the Kingsbridge inlet 

 south of Charleston, and strikes thence by Frogmore to the south 

 * Apparently intrusive. 



