586 



is associated with finely-grained fissile sandstone. From this distri- 

 bution, the autlior infers, that the conglomerate marks the original 

 shore of the sea in which the new red system was deposited; the 

 sandstone, the finer detritus carried to a certain distance from it ; 

 and the marl, the mud diffused through the water, and conveyed to 

 a still greater distance. The jointed structure is not very distinct, 

 but it may be traced even in the conglomerates ; and from the best 

 exhibited cases, the author concludes that the strata are divided into 

 octohedral masses. Vegetable remains are found near Sidmouth. 



(rf.) Culmiferous or Carboniferous Series. — After alluding to the 

 rectification, in 1836, by Prof. Sedgwick and Mr. Murchison, of the 

 error in the geological position of this series, Mr. Austen states that 

 it occupies, in South Devon, the whole of the valley between Great 

 Haldon and the extremity of Dartmoor. 



He subdivides the series as follows : — 



1st. Shales, which near the granite or trap, sometimes resemble 

 the older slates. 



2nd. Sandstones with beds of thick flagstone, as above Greyleigh 

 and Biddlecomb, and below Lewell House. 



3rd. Conglomerates, as at Ugbrook, the Orchard Well valley, and 

 above Ryder Farm. 



The limestone of Chudleigh is stated to rise through the culmi- 

 ferous strata N. of Ugbrookrpark, and to the S.W. of the Bovey de- 

 posit, to form a continuous band. 



The mineral contents of the series are various. Tin and copper 

 occur beneath Ashburton Down and near Christow ; lead has been 

 found in the same parishes ; and iron ore is contained in large quan- 

 tities in the shale. Where the rock approaches the granite, it is 

 much altered, and encloses numerous small garnets. Remains of 

 plants are scarce, but impressions of Calamites have been found ; and 

 minute portions of vegetable matter occur in some of the beds of 

 sandstone. 



Transition System. — The culm measures rest unconformably on 

 a series of deposits belonging to this system, and divided by the 

 author into the following formations, in descending order : — 



1. Rag Limestone. — A calcareous rock, coarsely laminated, of a 

 dirty red colour, and abounding with stems of encrinites. Locality, 

 Forest of Denbury. 



2. Shale. 



3. Great Limestone. — This is the limestone of Newton Bushel 

 and Torquay. It is distinctly jointed, the prevailing strike of the 

 joints being, for one set, N.N.W. to S.S.E., for the other, W.S.W. 

 to E,N.E.; but considerable variations are stated to occur in dif- 

 ferent quarries. 



Organic remains are very numerous, both corals and shells. At 

 its base the deposit presents several alternations of shale and black 

 limestone, and contains some peculiar fossil shells. It passes gra- 

 dually into the next formation. 



4. Argillaceous Slates and Sandstones, generally Red. — This de- 

 posit is of great thickness, forming the principal part of the slate- 



