372 



THE GEOLOGIST. 



the mammoth, the great herbivora, and the cave-animals ? Have any investi- 

 gations of the deposits in which snch relics have been fonnd ))een made 

 with sufficient care in any instance to determine their proper geological age ? 

 I think snch cases are well worthy of consideration in reference to the present 

 highly interesting geological topic. — Yours truly, F. S. A., London. 



t^RETACEors Rocks iis^ Norfolk and Suffolk. — Sm, — On what geological 

 formation are the cretaceous rocks in Norfolk and Suffolk superposed. — T. 

 Waud, Ickworth. — Por the most part, we believe, on the Kimmeridge Clay. 



REVIEWS. 



Geological Survey of Canada. — Report of Progress for 1857. Toronto : J. 



Lovell. 1858. 



The report of progress of the geological survey of an important colony like 

 Canada must always be, w'. atever the merits of the report, a matter of 

 much interest. It is a matter of interest alone to know how much or how 

 little has been accomplished. The report which has recently been forwarded 

 to us is that for the year 1857, presented to the Legislative Assembly on the 

 31st March, 1858. 



One interesting item in it is the survey of the Huronian formation (the 

 equivalent of our " Longmynd" rocks) along the north shore of Georgian Bay, 

 the chief seat of copper-mining in Canada. 



The rocks of this region are much distorted and dislocated, and those ex- 

 amined in the district around Lake Echo are altogether of Huronian age, with 

 the exception of the flat parts near the shores of Lake George and the St. 

 Mary river, which are probably unconformable SHurian strata. In order to 

 follow out the structure of these altered and contorted Huronian rocks, a band 

 of associated Hmestone was selected as the best developed feature, as well for 

 its peculiar mineral character as from the presence above and below it of a 

 very remarkable conglomerate. This band was followed for considerable dis- 

 tances, and is about two hundred feet in tliickness. It presents alternate 

 layers of pale blue or whitish limestone and greenish calcareous and siliceous 

 slate, usually in thin strata. About the middle of the mass there is a calca- 

 reous breccia, generally iii a massive bed, containing angular fragments of 

 greenstone, trap, and dark blue or blackish impalpable gramed slate. 



The slate-conglomerate, both above and below the limestone, contains 

 numerous rounded pebbles of various kinds, chiefly of syenite, quartz, gneiss, 

 and jasper. The rocks beneath the lower slate-conglomerate are greenish 

 siliceous slate and pale greenish quartzite ; these are underlaid by greenstone, 

 and below is a highly altered green cliloritic slate, which is exposed in nearly 

 vertical strata, forming high precipices at the extreme head of the lake. 



Above the upper slate-conglomerate a thinly laminated dark blue or blackish 

 slate of very fine texture was observed interstratified with thin beds of dark 

 grey quartzite, overlaid by whitish or pale grey quartzite in some parts suc- 

 ceeded by a mass of greenstone, and m others gradually passing upwards into 

 a quartzose conglomerate ynih. blood-red jasper-pebbles. 



Great masses of trap appear to be iiTcgularly interposed among the strata, 

 which are also intersected by numerous fine-grained, compact, greenstone dykes. 



The order of succession and the thickness of the beds are tlnis given :— 



