GEOLOGY 



The subdivision of the New Red rocks, completed in 1880, was not 

 published till after the appearance of the new series i inch maps (sheets 

 325, 339 and 350), to which the lines were transferred from the old 

 ordnance sheets 21 and 22, part being still unpublished. 



The mica-schists and altered igneous rocks of the Start, Prawle 

 and Bolt districts were claimed as Archaean in 1874 by Professor Bonney, 

 which opinion, subsequently endorsed by Miss Raisin, was combated by 

 A. R. Hunt and other writers in favour of an extremely altered phase of 

 the neighbouring Devonian rocks. The New Red succession on the 

 coast given by Whitaker was amplified and extended throughout the 

 county and the results published by Ussher, The Rev. A. Irving and 

 Professor Hull propounded classifications of the series, in which the 

 Budleigh pebble bed was taken as the base of the Trias. The whole 

 series had been regarded as Keuper by Pengelly. The Cretaceous rocks 

 have been investigated by Fitton, Meyer, the Rev. W. Downes and 

 Jukes-Browne. The Bovey clays and lignites, described as Miocene by 

 Pengelly and Professor Heer, were referred to the Eocene by Starkie 

 Gardiner. The plastic clay of De la Beche and supra-cretaceous gravels 

 were subsequently referred to the same general period (Bagshot) by 

 C. Reid. 



The cavern deposits of the Torquay and Brixham districts were 

 exhaustively worked and described by Pengelly, those of the Plymouth 

 district by R. N. Worth. The raised beaches and submerged forests 

 and other Pleistocene phenomena were treated by Pengelly, Hunt and 

 others. The study of recent marine action and of the submarine geology 

 of the English Channel has been prosecuted by A. R. Hunt. 



In the older rocks paljeontological research is represented by the 

 Tables of D'Archiac and De Verneuil in the Geological Society's 'Transac- 

 tions ; by Professor Phillips' Figures and Descriptions of Palaeozoic fos- 

 sils ; and (specially relating to the faunas of the Torquay and Newton 

 Abbot limestones, and of the Upper Devonian strata of north Devon) by 

 Whidborne's Monographs in the Palaeontographical. 



As regards the igneous rocks of the county, the granite has been 

 described by De la Beche and by many subsequent observers, including 

 R. N. Worth and General MacMahon ; the volcanic and intrusive 

 rocks of the Palaeozoic area by Champernowne, Rutley, MacMahon and 

 by Watts and Teall ; the volcanic rocks associated with the Lower New 

 Red by Vicary, Bernard Hobson and Teall. In the following table of 

 stratified rocks and deposits the highly altered rocks of the Start, Prawle 

 and Bolt are given the subordinate position, and will be first described 

 because they occupy the most southerly part of the county, have furnished 

 no fossils, and are marked off by their greater alteration and compression 

 from the Devonian rocks on the north, without prejudice to the prob- 

 ability that they may be an extremely altered phase of these rocks. 



