﻿Clement Reid-^-Cuhn-measures near CJmdleigh. 



455 



Acroculia veiusta, Phil. 

 Murchisonia angulata, Phil. 



,, spinosa, Phil. 



Natica ? 



Euomphahis serpens, Phil. 



Macrocheilus ? 



Fleurotomaria cirriformis, Sby. 



Prof. Phillips and Mr. Jukes suggested the existence of a fault, 

 and a detailed examination of the ground has enabled me to trace 

 a dislocation which will without difficulty account for the apparent 

 unconformability. 



Unfortunately sections of the junction of the Culm-measures and 

 Devonian Limestone are rare, but in the road south of Lewell 

 House, near Chudleigh, we have an exposure which has every 

 appearance of a passage. The upper part of the Limestone is seen 

 to become more and more shaly, then to pass into alternations of 

 shale and limestone; and gradually grit, at first fine grained, replaces 

 the calcareous beds. Still higher there is thick-bedded sandstone 

 like that in the lower part of the Culm-measures of Ugbrooke Park. 

 The upper part of this section is not clearly exposed, though it 

 seems to indicate a passage. 



At Lower Dunscombe Quarry the Limestone again passes into 

 limestone-shale containing Clymenia valida and C. striata (as identi- 

 fied by Mr. Etheridge). Unfortunately the junction with the Culm- 

 measures is not exposed; but as far as can be judged from the stones 

 in the adjoining fields, it is similar to that shown in the last section. 

 It is noticeable that the species of Clymenia have not been found in 

 the solid limestone, but only in the few feet of calcareous shales 

 above it. 



A more difficult question has arisen from the abrupt ending of the 

 Limestone on the west of Chudleigh and its sudden replacement by 

 Culm-measure shales. The small patch at Waddon Barton is nearly 

 horizontal, and entirely surrounded by green and purple Devonian 

 slates ; the isolated position of this limestone is caused by de- 

 nudation, and a slight flexure of the beds will connect it with the 

 main mass. A short distance to tlie west a fault runs in a north 

 and south direction, throwing down Culm-measures against the 

 slates ; this fault I have traced northward to Whiteway Plouse, 

 where the Limestone and Culm Shales are thrown together. The 

 fault then disappears beneath the Triassic rocks of Haldon, ap- 

 parently without affecting them. To the south the dislocation can 

 be traced to near Lower Herkley, beyond which I have not ventured 

 to continue it, as there are only slates and sliales for guidance. 



Mr. Godwin-Austen, in his " Geology of the South-east of Devon- 

 shire," mentions a well dug at the house on the west side of Chud- 

 leigh rock. This showed about fifteen feet of horizontal carbonaceous 

 shales and sandstones resting on highlj^ inclined claret-coloui'ed slates 

 dipping in the same direction as the Chudleigh Limestone. Mr. 

 Austen considers that this is an instance of unconformability ; but on 

 quite independent evidence, and before I had iioticed the account of 

 this well, I had been led to trace the fault through this exact spot. 

 A considerable hade to the fault will account for all the appearances 

 in this and some other sections noticed by Mr. Austen and Sir Henry 

 De la Beche. 



