404 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [April 22, 



up by Coades Green, Congdon, and Trevadlock, and by the north of 

 Nighton nearly to Alternan. The lowermost beds here appear to be 

 argillaceous ; and although sometimes black, as at Trevry, Trevadlock, 

 and Trevage, they are liable to become whitened, or of a very pale 

 colour, from exposure, and are then sometimes difficult to separate 

 from the underlying rocks. Xorth-east of Xighton the grey grits 

 have been quarried at the edge of a wood near the turnpike road, 

 where the beds dip ^S", 20° W. at 15°, and are in the same mineral 

 condition as at Trelabe, and on the banks of the Inny below Trecarrel 

 Bridge ; and in some of the beds plant-remains are numerous. 

 All the high ground on either side of the turnpike-road from the west- 

 ward of Alternan to Coades Green is capped with these beds, the 

 grits weathering to a greenish yellow colour, and becoming whitened 

 on the surface, and the slates becoming pale and soft, and then so 

 much resembling some of the underlying series that it is difficult to 

 distinguish them lithologieally. ]S"ear Trelask House there is a small 

 off-standing patch of the Culm-measures dipping E. 10° 'S., overlying 

 the ash-beds of Lawannick ; and two other outliers occur on the 

 opposite side of the Inny : — the one on the west of Pollinny, where 

 the beds dip north-east, and rest on slates that contain Spinfera dis- 

 juncia and other fossils ; the other to the south of that place, occupy- 

 ing the high ground on either side of the road to Lamick, with a 

 dip a little to the east of south. 



Lower down the Inny these beds are well exposed at Beals Mill, 

 where they contain Goniatites, Orthoceras, and plant-remains, as 

 noticed by Professor Phillips ; and they include the grits of Mount 

 Pleasant and Inny Foot, which are continued past the Swiss Cottage 

 and Twowell Down towards Lammerton. These beds dip southerly, 

 but, as they undulate on their line of strike, they deviate occasionally 

 by 25 to 30 degrees from due south. Thus atTregarvis the dip is 

 S. 10° E. ; at the Xew Bridge over the Inny on the CaUington Road 

 it is S.S.W. ; at Beals MiU it is southerly ; at Inny Poot S. 10-20° 

 E. ; while at the Swiss Cottage it is S. 35° W. This southerly dip 

 is continued across the Inny for at least half a mile ; but south of 

 Tregvis, I^orton, and Kingston the dip is reversed, and about Pen- 

 pill we reach the southern limits of the Culm-measures, with the 

 exception of an outlier which caps the high ground between Linking- 

 horn and Southhill. 



From Penpill the line which limits the Culm-measures on the 

 south follows the ridge of high ground by Yenterdon and Stoke 

 Climsland to Lidwell, and thence nearly to Horse Bridge. At the 

 crossroad north of Stoke Climsland there are some black slates with 

 chert bands, partly weathered white on the surface ; and similar Car- 

 bonaceous slates, partly blanched from exposui-e, are seen half a mile 

 to the north of this place on the road to Beal's MiU. These are fol- 

 lowed by dark slates with grey grits quarried at Lower Down House 

 and Row Down, similar to those of Lawannick Down and Tregvis. 

 In descending the hiU to Horse Bridge we pass from these dark slates 

 and grits with a northern dip on to grey roofing-slates, dipping appa- 

 rently to the west. These underlying slates, with the same westerly 



