458 



Mr. Austen on the 



to Totness the carbonaceous beds occur on the east side of the great mass of Conator 

 limestone ; and on the opposite side they abut against a vertical wall of limestone, 

 acquiring considerable thickness, and in the lower portion present the same alter- 

 nations of carbonaceous shales with siliceous bands as the culm series of North 

 Devon. The pebbles of the conglomerate beds are mostly siliceous, and may have 



Fig. 10. 



Unconformable position of the carbonaceous deposits (a) to the older rocks {b) near Newton. 



been derived from the quartz veins of the older slates ; but in the section repre- 

 sented by Fig. 9. the lowest beds are seen to contain blocks of limestone derived 

 from the subjacent rock, and mostly angular or but slightly water-worn. The 

 unconformable position of this mass can also be observed along the road from East 

 Ogwell to Newton, and in the valley near Bradley House. 



The rocks of Ugbrooke Park closely resemble those of Rydon Hill, consisting of 

 the same black earthy shales, coarse sandstones, and siliceous conglomerates ; but 

 their superficial extent is much greater. They moreover contain pebbles of green 

 porphyry, and of a black flinty rock like Lydian stone ; but in the numerous beds 

 of this conglomerate which I have examined, 1 have never detected a fragment of 

 granite. Their position, like that of the Rydon deposit, is unconformable, as may 

 be seen south of the Lewell stream, near the Chudleigh Rock, and in the sections 

 represented in PL XLH. fig. 6, fig. 8, E. Vegetable remains may be found in the 

 sandstone quarry, by the road leading from Chudleigh to Whapple-well, and in 

 Ugbrooke Park generally ; impressions of large Calamites occur also in the Orchard- 

 well valley, but not sufiiciently well preserved for the determination of the species. 

 We may safely conclude, that these deposits are of the age of some portion of the 

 true coal-measures of the other parts of England. 



The culm series of Professor Sedgwick and Mr. Murchison undoubtedly passes 

 round the eastern side of Dartmoor, and is in contact with the granite as far south 

 as Skeriton, a little west of Dean Prior (see map, PI, XLL). Along its external 

 edge it first rises, about Exeter, from beneath new red sandstone ; near Chudleigh 

 its relations to the calcareous masses of the base of Great Haldon are rather ob- 

 scure, and such is also very generally the case in its course westward. There can 



