310 Bernard Hohsou — Permian Breccias of S. Devon Coast, 



Plate XVII. 

 Fig. 



1. iSeaphiocwlia {?) africaim, sp. nov. Nat. si/e. Side view of internal cast. 



Gomitz River, 

 la. Ditto. Same specimen. Anterior view of shell. 

 \b. Ditto. Same specimen, viewed from dorsal (brachial) side. 

 Ic. Ditto. Same specimen. Umbonal region of pedicle valve, inverted to show 



detaOs of structure. 



2. Ditto. Another smaller specimen. Nat. size. Side view of internal cast, 



showing ribbing of shell. Same locality. 



'la. Ditto. Same specimen. Nat. size. Anterior view. 



'2b. Ditto. Same specimen. Nat. size. Viewed from dorsal side. (The right- 

 hand upper portion of shell is obscured by matrix.) 



3. Ditto. Another specimen. Nat. size. Umbonal region of an imperfect 



individual, with shell adhering to cast of pedicle valve. Same locality. 

 3rt. Ditto. Same specimen. Nut. size. Full-face view, showing sharp incurved 

 beak of pedicle valve. 

 d. diductor muscles ; a. adductor muscles ; c. bases of crura ; d.p. dental plates ; 

 /. foramen in beak of pedicle valve ; p. central pit in hinge-plate ; 

 t.r. transverse ridge in umbonal cavitj' of pedicle valve ; m.r. median ridge 

 in brachial valve. 



JN.B.— With the exception of the specimens PI. XVI, Fig. 1, and PI. XVII, 

 Fig. 3, which are in the Sedgwick Museum, all the above types are in the South 

 African Museum, Cape Town.] 



HI. — The Origin and Mode of Formation of the Permian 

 Breccias of the South Devon Coast. 



By Beuxard Hobson, M.Sc, F.G.S., 

 Lecturer in Petrology and Geology in the Victoria University of lilauchester. 



(PLATE XXI.) 



AFTER visiting in 1905 the excellent exposure of the Permo- 

 Carboniferous Dwyka Conglomerate, containing glacially 

 striated boulders, overlj'ing glacially striated Barberton beds at the 

 foot of Gotshe Mountain in the Vryheid district of Natal, ^ it occurred 

 to me to examine the Permian breccias of the South Devon coast 

 to see whether I could find any evidence of their being of glacial 

 origin. 



Tl)e breccias in question have been frequently described, but, 

 so far as I can find, the published information is very vague in some 

 respects, more particularly as to the size of the fragments, blocks, or 

 boulders composing the breccia which, in most cases, are simply 

 described as large or small, than which nothing can be more 

 indefinite. 



As large blocks are much more easilj"- transported by ice than by 

 water, I paid special attention to the size of the blocks. The 

 localities visited lie between Koundham Head, Paignton, on the 

 south, and Dawlish on the north, and are shown on the Geological 

 Survey maps (new series), Sheets 339, Teignmouth (1899), and 350 

 Torquay (1S9S), and the breccias referred to are those overlying the 

 Watcombe Clay and marked e- on the Survey maps. 



1 See G. A. F. MoleugraafE, " Geoloffy of the Transvaal," Edinburgh, 1904, 

 p. 66. 



