Reviews — Duparc 8f Pearce — Geologij of N. Urals. 327 



the washings of granite uplands, standing respectively in near 

 proximity to the areas of deposition. 



I believe the idea of a granitic source in what is now the Channel 

 first occurred to me from observing many crystals of pink felspar, 

 very little rolled or broken, lying on the surface of the heath a few 

 miles east of Dorchester. This was more than fifty years ago ; but 

 I think the locality will be found near the spot marked " Dick of 

 the Banks" on the ordnance map. Unless I am mistaken the felspar 

 of Dartmoor is white or grey, so that these crystals being pink 

 points to a different source of origin. Boulders of plutonic rocks 

 occur on the shore at Selsea, showing that such rocks must have 

 existed in the Channel area. 



As to the question whether such a subaerial source of granitic 

 detritus as I have suggested can have existed in the Channel area 

 during Eocene times, we find that God win- Austen considered the 

 Channel to be a valley of depression, and thought that it might have 

 been dry land until Pleistocene times ; while his contour chart of 

 the sea bottom shows a remarkable shoal, rising within seven 

 fathoms of the surface, nearly opposite the eastern end of the Isle 

 of Wight.^ May not this indicate the position of the remnant of 

 a former boss of granite ? 



la IB "V I IE "W S. 



I. — Eeoherohes Geologiques et Petrographiques sur l'Oural 

 DU NoRD. 2nd memoir. By Professor L. Duparo and Dr. F. 

 Pearoe. Mem. Soc. de Phys. et d'Hist. Nat. de Geneve, 

 vol. xxxiv, p. 383 (1905). pp. 219, 1 map, 5 plates, 30 figures, 

 and 29 cuts in text. 



rpHE first part of this memoir, dealing with the physiography of 

 \_ the Northern Urals and the petrography of Mount Koswinsky, 

 appeared in 1902, in an earlier fascicule. Like it, that before us 

 exhibits the most conscientious elaboration of every detail, especially 

 petrographic — possibly sometimes carrying this almost to an excess 

 — and describes the Tilai-Kanjakowsky-Cerebriansy chain, with the 

 petrography of its rocks and their modes of occurrence from west to 

 east, from the watershed between the two continents up to the Devonian 

 of Koswa. It contains illustrations of scenery which confirm the 

 impression, produced by the former part, that for a comparatively 

 mountainous region it is bare and rather monotonous. Its rocks 

 of deep - seated origin are : (a) pyroxenites with olivine and 

 magnetite ; (6) gabbros of various types and structures, often con- 

 taining olivine; (c) gabbros with uralite and diorites : the hornblende 

 abundant, the olivine rare ; {d) norites with hypersthene and 

 diallagic diopside ; (e) dunites with partially serpeutinized olivine 

 and chromic iron. The dyke or vein rocks are : (a) dunites, often 

 more completely serpeutinized; (6) berbachites (granular. aggregates 

 of diallage, magnetite and Labrador felspar) ; (c) hornblendic 



1 " On the Valley of the English Channel " : Q. J.G.S., vol. vi. 



