SERIES OP THE DEVON COAST-SECIION. 163 



investigated it, to be " the final product of the vreathering of different 

 trachytie rocks, and to be essentially related to laterite" Wolf 

 distinguishes in Northern Hungary the diluvial marginal deposits of 

 the mountains from the contemporaneous deposits formed in aqueous 

 basins. The former he describes in ascending order as breccias 

 (Schotter), Nyirok, and Loss — the latter as drift-clay, drift-sand, 

 and Loss-sand. Stur, again, draws a distinction between the "moun- 

 tain-loss " and the " valley-loss," the latter containing freshwater 

 molluscan remains *. By comparative reasoning it is not difficult 

 to assign a similar terrestrial origin to the Permian Marls ; and this 

 is a sufficient explanation of their entirely unfossiliferous character. 

 The siliceous rocks of the ancient mountain-sj^stem, of which the 

 palaeozoic land of Devon, Cornwall, and Brittany are the remains, 

 would furnish by their subaerial destruction the materials for both 

 the breccias and the marls, the intrusion of the Dartmoor granite 

 massif being in all probability connected with the great upheaval, 

 which would give us both the supply of materials and the conditions 

 for rapid disintegration and degradation of the mountain-land of 

 the south-west which our hypothesis requires. 



The intensely ferruginous character also of the breccias, sands, 

 and marls alike (the state of the irony investment indicating con- 

 temporaneous precipitation by oxidation) points indirectly to 

 immediate Post-Carboniferous times, for the extensive waste of 

 vegetation which would be required to furnish the natural solvents 

 which produced the solutions from which precipitation was effected. 



DiSCTJSSION. 



The President pointed out the interest attaching to the question. 

 The absence of Prof. Hull and Mr. Ussher was to be regretted. 



Mr. Smith Woodward called attention to a supposed s]3ine figured 

 by Mr. Metcalfe in the last contribution to the present subject, 

 published in the Society's Journal (vol. xl. p. 260). Prof. Huxley's 

 recent researches upon Triassic Rhynchocephalians enabled this 

 fossil to be determined as a portion of the premaxilla of Hypero- 

 dapedon. 



■* See also Senft's description of the formation (Bildungsmassen) of the Roth- 

 liegendes of North-western Thiiringen, ' Gaea, Flora und Fauna der Unigegend 

 Eisenachs,' pp. 29, 30. 



