A HISTORY OF DEVONSHIRE 



Worth ' records the occurrence of clayey earth with scattered pebbles 

 of quartz, schorl rock, grey grit, felspar, hornblende schist and brown 

 pumiceous rock with iron ore and vein stuff. In this deposit patches of 

 white clay, similar to Bovey clays, are present. The pebbles range up 

 to over 12 lb. in weight. The gravelly clay rests on white, drab, 

 cream-coloured and red sand, fine and quartzose, and coarse and schorla- 

 ceous. These deposits also occur in hollows in the limestone of Catte- 

 down. 



On the northern slope of Cattedown, 60 to 70 feet above datum, 

 Worth discovered a gravel deposit in clayey subsoil. The pebbles, run- 

 ning up to 3 1 lb. in maximum weight, betrayed derivation from fissures 

 in the limestone, being partly encrusted with stalagmite. Flint (mostly 

 chalk flint) pebbles, well rolled and up to 2 lb. in weight, formed 40 

 per cent, and in another place 67 per cent, of the stones ; next came 

 schorl rock and quartz ; amongst the limestone pebbles one of Lias 

 limestone, two probably Culm limestone, and one of freestone like Beer 

 stone, were found. Stones of grits of various kinds, of Culm chert 

 (probably), Elvan and other granitoid rocks, shalstein, diabase, epidiorite, 

 andesite, volcanic grit (probably from the Wearde-Efford beds= .? Middle 

 Culm) were also found. Whether the above are Tertiary or remanies of 

 Tertiary or early Pleistocene gravels is not apparent. 



PLEISTOCENE 



Gravels left at considerable heights above the adjacent or neighbour- 

 ing lines of drainage, marking early stages in the elaboration of the 

 existing contour, are met with in the watersheds of the Exe and its 

 tributaries, and less frequently in the valleys of the Palaeozoic area. 

 These gravels are composed of materials derived from the catchment 

 areas in which they occur. Flint and chert are usually more or less 

 abundant in the old gravels on the cliffs near Dawlish and east of 

 Exmouth. 



In the Pebble-bed districts, west of Ottery St. Mary and near Bud- 

 leigh Salterton, their materials have been so largely re-deposited that it 

 is difficult to define their actual limits. A good instance of re-deposition 

 of Lower New Red sands and breccia is shown in the railway cutting 

 between Langstone Point and Dawlish," where it overlies an old gravel 

 of the Exe, composed of well rolled flint, chert and derivatives from 

 New Red breccia, which rests at 70 feet or more above datum, on sand 

 and breccia (excepting inclined indications of bedding, very similar to 

 the re-deposit). The coasthne at the time the old gravels east and west 

 of Exmouth were deposited was situated a considerable distance seaward 

 of its present limits, and some of these gravels were probably contem- 

 poraneous with the raised beaches. 



' R. N. Worth, 'On the Geology of Plymouth,' Trans. Plymouth Instit. for 1875 ; ' Some Detrital 

 Deposits associated with the Plymouth Limestone, Trans. Roy. Geol. Soc. Com. for 1888. 



= Ussher, 'On the Mouth of the River Exe,' Trans. Devon Assoc. 1878; 'The Geology of 

 Pawlish,' Tram. Devon Assoc, 1881. 



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