Geology of the South-east of Devonshire. 485 



contents of a north and south joint, from which the solid rock has been removed 

 on each side : the same quarries afford many analogous instances. All the joints in 

 a mass of arched limestone near Barton have been similarly opened and filled ; and 

 these, as well as all the fissures which are to be found along the base and west 

 slopes of the Haldons, as at Orchard-well, Lindridge Hill Wood, &c., suggest that 

 the strata must have been subjected to great tension, which caused them to yield 

 along the joints as lines of least cohesion. 



The whole period of denudation was probably one of slow emergence and 

 gradual abrasion at successive levels ; and that of the formation of open chasms 

 towards the close of the same period, when the country reached its greatest eleva- 

 tion as dry land. 



Along the entire line of the Haldons just described, there is abundant evidence 

 of a great rise of the beds to the east ; and the amount of this elevation is best 

 ascertained by the relative position of the greensand deposits of Haldon and Bovey, 

 which must have been at the same level, and under precisely similar conditions, 

 when formed. The height of Little Haldon above the sea at Teignmouth is 890 

 feet ; but at least half the thickness of the greensand of the Bovey valley must be 

 below the level of the sea, so that there is a difference of 800 feet in the present 

 positions of beds once continuous. This elevation took place perhaps slowly, but 

 at the same time with that general rise of all the south of England, which happened 

 towards the close of the tertiary period ; and it is possible that previous to this 

 event the whole was submerged as far as the high lands of the west of England ; 

 and I believe it was then that the pebbles of granite, schorl and quartz were distri- 

 buted over what are now the summits of the Haldon and Blackdown hills. 



Subsequent to this period of denudation, and under the same conditions with 

 the fissures of the limestones, were formed those great fractures along one of which 

 the Teign flows as far as Chudleigh, also the parallel valley from Bovey to More ton, 

 and the origin of which was evidently connected with the numerous abrupt move- 

 ments that produced the deep valleys in the granitic region of Dartmoor, and which, 

 being but little above the level of the sea, can have no great antiquity, as they are 

 unoccupied by any sedimentary accumulations. 



The lower part of the course of the Teign, like that of the Exe and many other 

 streams, is through a valley of excavation along a line of fault f. its course is due 

 east and west, and it will be seen that the mouth of the Teign is the only point along 

 the coast-section of the new red sandstone formation, where the strata have an 

 anticlinal dip to the north and south (Map, PI. XLL), Higher up the valley, and 

 on the north bank, opposite Combe-cellars, is a fault which for more than half a 

 mile, in an east and west direction, brings up the slate in vertical juxtaposition 

 with beds of new red sand ; the downcast, as usual, being to the west, but the 



VOL. VI. SECOND SERIES. 3 R 



