1868.] ROLL — SOUTH devon and east cornavall. 431 



face between Ash and Higher Yalberton on the north, and Sharkhara 

 Point, near Brixham, on the south. The great mass of limestone of 

 Berry Head, which stretches inland to Walton, and of which the 

 Yalberton and Stoke Gabriel limestones are but detached portions, 

 forms an arch, which is depressed in its central portions between 

 Walton and Eishcombe Point : while its southern margin is thrown 

 over an anticlinal axis at Mudstone Sands, and is seen at Sharkham 

 Point and Brixham dipping under the higher beds on the south, its 

 northern edge, between Higher Yalberton and the coast, is doubled 

 under with inverted dip. The Stoke Gabriel limestone is thrown 

 up on the north-east by a fault, which extends from the village by 

 Howell to the south-west of Ash, and has brought it against the 

 higher beds which range up from Ashsprington. On the north, this 

 limestone dips under the purple slates and grits of Windmill Hill, 

 and near Higher Yalberton some slates are troughed in a fold of 

 the limestone. 



A long narrow anticlinal axis commencing at Yealmpton ranges 

 by Broadway and Cornworthy, and thence to Brixham, where at 

 Mudstone Sands it appears to be again narrowing to a termination ; 

 and a second anticlinal axis to the north of the former commences 

 nearLudbrook and runs, by the north of Roster Bridge and between 

 Perchwood and Tuckenhay, to the south-east of Stoke Gabriel. These 

 anticlinal axes have brought up the lower slates with an overthrow to 

 the north. If we follow the Hue of strike between the fossiliferous 

 slates and the base of the overlying limestone from Brixham past 

 Lupton House to the limestone of East Cornworthy, and thence to 

 Middle Washburton and the Avon below Broadly and the north of 

 Modbury, to the limestone of Palmer's Cross, which is clearly on the 

 same line of strike as that on the south side of the anticlinal axis at 

 Yealm Bridge, — and again in an opposite direction through Ermington 

 and the limestone of Shilstone to the Avon at Beckham, and thence 

 back by Fowlescombe to Ludbrook, and again from Ludbrook by 

 North Hewish, Diptford, Harberton Eord, and Perchwood to the 

 west of Stoke Gabriel, — such line will indicate pretty nearly the 

 limit between the upper and lower slates, and the place of the Tor- 

 bay limestones, which, however, in the part of the country between 

 Totnes and the Yealm, are only feebly represented at a few points. 



The limestone at Yealm Bridge is partly dolomitized. It forms 

 the crest of the anticlinal axis, but is depressed on the south towards 

 Torr. On the north it is underlain by a bed of volcanic rock, from 

 off which it has been partly removed by denudation, the thinner 

 edge at Ketley and the small patch on the north side of the axis at 

 Yealm Bridge alone remaining. 



There stiU remain to be noticed the several masses of Devonian 

 limestone which protrude through the Culm-measures on the norths 

 east of the Bovey basin ; but there is no apparent reason for sepa- 

 rating any of these masses from those of Ogwell and Kings Kerswell, 

 The Chudleigh limestone has been already noticed when describing 

 the Carbonaceous rocks, and perhaps from its position it might 

 be regarded as belonging to the Ashburton range : but the fossils 



vol,. XXIV.— part I, 2 u 



