278 Reviews — G. F. MaWieic — Cambrian Faunas. 



There is a marked unconformity between these strata and the over- 

 lying Eocene shales and limestones, which consist of two divisions, 

 the Serrai limestones and the Esna shales, respectively of Londinian; 

 and Suessonian age. Andesites have been intruded into these beds, 

 which are succeeded by Pliocene rocks, Oligocene being absent, and 

 Miocene beds occurring only in the extreme north-east of the area. 

 The Red Sea is considered to have come into existence in late Pliocene 

 times, as the highest coral reefs (200 metres above sea-level) 

 contain a possible mixture of Pliocene and Pleistocene corals. The 

 youngest coral reefs are associated with gravels and conglomerate* 

 which must be of Pleistocene age. 



Special chapters are devoted to Economics, which include gold 

 and petroleum, and an interesting discussion is raised on the 

 "Influences giving rise to the Eastern Desert structure." These 

 influences may be summed up as follows : — (1) Its geological 

 structure ; (2) tectonic movements, folding and faulting, breaking 

 up the plateau into isolated areas ; (3) water ; (4) insolation and 

 changes of temperature ; (5) mineral composition of the rocks and 

 differences of their coefficients of expansion ; (6) the dykes, as 

 strong determinative factors in the hill sculpture ; (7) wind, only 

 effective where it has a supply of sand and plenty of space to act ; 



(8) Nubian sandstone, and not granite, is the source of the sand ; 



(9) sand action, in eating away the limestones along previously 

 formed cracks. 



The general get-up of the volume is highly satisfactory, the 

 printing of the text, maps, and sections, which has all been done in 

 Cairo, is excellent, the photogravures are by Albert, of Munich, and 

 there is a singular absence of misprints. There is a voluminous 

 index and a good bibliography, both quite indispensable to such 

 a report. We would, however, ask the Director to insert the word 

 "Egypt" after the word "Ministry" in the covers and title-pages 

 of these reports, and to believe that the future difficulties which will 

 arise from a book dated 1902, but not issued till 1903, are more 

 real than at first sight appears. We are grateful for the list of 

 publications which appears on the back of the cover, for in an 

 unnumbered series of publications one is never certain how 

 complete or incomplete one's set may be. C D. S. 



VI. — Notes on Cambrian Faunas. By G. F. Matthew, LL.D.j> 

 with description of a new species of Metoptoma. (Trans. Roy* 

 Soc. Canada, series ii, vol. viii, sec. iv, p. 93.) 1903. i. 



THIS article deals with several subjects relating to the Cambrian 

 faunas of Canada. In the first note the differences in musculation, 

 circulatory system, etc., of the Oboloid shells of the Cambrian in 

 Canada are described. It is claimed that these shells belong to 

 several subgenera. All but one are older than the type of the genus, 

 Obolus Apollonis. 



In the second note the enlargement during Cambrian time of the 

 shells of several genera of Cambrian Inarticulate Brachiopoda is- 

 shown to have taken place. 



