168 DREDGINGS OF THE MARINE BIOLOGICAL ASSOCIATION: 



De la Beche, vvliose work stands as a model of careful discovery 

 and accurate inference, with reference to the red trap of Cawsand 

 writes : " Though unable to adduce direct proof, we are inclined to 

 refer this porphyry, from its general character, to the date of the 

 lower part of the red sandstone series, and to infer that it may be 

 connected with a portion of that series beneath the sea in the direction 

 of Bigbury Bay, on the coast of which, near Thurlestone, we find the 

 patch above noticed."^ 



In 1867 Pengelly, and in 1886 Worth, supplied proof and 

 confirmation as to the age of the 'porphyry.' And in 1898 the 

 writer, as the result of Dr. Allen's dredgings, was able to assert that 

 there was strong evidence that from the Hand Deeps to Bigbury Bay 

 the New Red rocks were continuous. It may now be added that 

 conglomerates dredged from off the Mcwstonc Ledge are distinctly of 

 the New Red type. In the gravels and sands between the Eddystone 

 and the Bolt New Red materials everywhere constitute a considerable 

 percentage of the rock fragments. 



In the vicinity of the Eddystone and the Hand Deeps New Red 

 rocks are found in situ (wherever rock is exposed), through which 

 protrude the reefs. The conglomerate at the Hand Deeps contains 

 fragments of the local schists and gneisses. 



The lithology of these rocks having been fully treated of in the 

 first part of the paper, it is not proposed to make any repetition here, 

 but pages 144 to 148 inclusive may be referred to. Although the 

 variety of the rocks is considerable, all, or almost all, appear to be 

 Triassic rather than Permian in character. 



Only one of Hunt's specimens has any bearing on this formation, 

 and that is H. 10, S. Edd., 20 miles — " Triassic Sandstone." 



Worth's discoveries further westward, meeting and overlapping the 

 Association's latest dredgings, are of especial importance ; these carry 

 the Trias to a point W. 5, S.W. by S. (mag ) Dodman, 25 miles, roughly 

 36 miles from the Eddystone.^ He doubted the eastward extension of 

 the outlier, on evidence which has interest as confirming the Associa- 

 tion's results. In fact the Trias does so extend, but his two eastern- 

 most points lay one on either side of the broad belt which it forms. 

 His W. 12, S. by E. Dodman, 27 miles, lies about 3 miles north-east 

 from M. 29, and at the latter point we now know that the Trias has 

 given place to higher strata. W. 12 yielded no Triassic rocks. 



His W. 6, S. by W. Dodman, 20 miles, in addition to a salmon-tinted 



1 Report Oil the Geology of Cornwall, Devon, and IVest Somerset, p. 212, 1839. 

 ^2 "On a Submarine Triassic Outlier in the English Channel," Q.J.G.S., Vol. XLII, 

 1886, p. 313-15. 



