436 PROCEEDINGS OF THE &EOLOGICAL SOCIETY. [April 22, 



If in like manner we follow the more southern belt of arenaceous 

 rocks from the north of Kingswear, we find purple and grey grits 

 south of Ditsham Cross at Bugford and south of Blackauton ; and 

 hard reddish slates, similar to those at Kingswear, occur on the same 

 line of strike at Loddeswell and Hatch Bridge; and with these 

 slaty and arenaceous beds are associated some bands of a peculiar 

 volcanic rock consisting of felspar and a foliated greenish mi- 

 neral resembling chlorite. These two belts of rock, therefore, be- 

 come separated, west of the Avon, by argillaceous slates which 

 occupy the country between Heathfield and Aveton GifFard, and be- 

 tween Kingston and the mouth of the Avon ; and as they dip under 

 the beds which strike up from LoddiswelL and East AUington to 

 Aveton Giffard and Bigbury, we must presume that they are lower 

 beds brought up ; but in what manner is not very clear. With the 

 grit-beds which strike down to the mouth of the Erme from Heath- 

 field Down there is some rock composed of quartz and felspar ; but 

 I did not meet with this rock in sihc, although heaps of it were 

 lying by the roadsides, and I was unable, therefore, to ascertain its 

 character or relations ; but the rocks on the east of this band of 

 quartz and felspar at Bednick, Broom Hill, and "Wakeham dip 

 south towards a mass of igneous rock, which at the quanw at the 

 eastern extremity of the mass appeared to be a bedded rock, dijDping 

 south and graduating upwards into the slates above. The variegated 

 argillaceous slates, which underlie the grits of Black Down and Lee 

 Moor, widen out as they trend round by Modbuiy, and with a 

 lessened angle of dip, and probably some undulation, range by Hol- 

 berton towards Xewton Ferrers, and occupy the whole of the country 

 between the Yealmpton limestone and the coast. It would almost 

 appear, therefore, that some line of fracture extends up from near 

 the mouth of the Erme towards Heathfield Down, and has cut out 

 part of the belt of arenaceous rocks which ranges up from Morleigh 

 Down and Lee !\Ioor on the east. 



It is difficult to bring the argillaceous rocks on the east of the 

 Yealm satisfactorily into connexion with those on the west of the 

 river, without supposing a line of fault to run up the stream from 

 the coast south of WorsweH. The beds which range down from the 

 south of Holberton appear to run out to sea at Stoke Point, and the 

 grits which stiike down to Erme mouth were not met with again on 

 the east of the Tealm. Light-coloured grits, however, occur in the 

 hill north of Knighton ; but it is not certain that they are a conti- 

 nuation of those of Staddon Point, although only grey and blue slate 

 was met "v\ith between the grit at Knighton and the Kmestoue at 

 Plymstock, without any appearance of the red grits of Staddon Point. 



These grey and blue slates stiike up from across the Tealm south 

 of Kitley Park, and from the north of Brixton, and appear on the 

 shores of Plymouth Sound between the limestone and Withy Hedge, 

 and contain some calcareous bands, especially near GoosweU. To the 

 south of these are the red grits and slates of Staddon Point, which 

 range inland to the south of Staddiscombe *, and. if continuous with 

 * :So. 6 in Prof. PhiUips's section. /. c. p. 201. 



