Xliv PfiOCEEDINGS OF THE GEOLOGICAL. SOCIETr. 



calcareous conglomerate, reposing in many places, nearly horizontally, 

 on granite of Devonian age. Chapter Y. is devoted to the con- 

 sideration of Albertite and the Albert shales. This remarkable 

 mineral, respecting the nature of which such different opinions were 

 entertained some time ago, is now shown to be an inspissated petro- 

 leum, occupying fissures in the Lower Carboniferous rocks along the 

 antichnal axes, and injected from below at two distinct periods under 

 considerable pressure. The author concludes by showing that its 

 source lies beneath the Albert shales — in other words, beneath the 

 Lower Carboniferous series — and that it is consequently of Devonian 

 or prior origin, and probably proceeds from rocks of the same age 

 as those which yield the petroleum of Pennsylvania, Ohio, and 

 Canada. 



The sixth chapter describes the rocks of the Devonian series, with 

 a full account of its vast mineral wealth, consisting of iron -ores, 

 copper, and argentiferous galena. These rocks are traversed by 

 many intrusive trap-dykes, having a general course from east to west. 

 Some of these traps are copper-bearing. The seventh chapter con- 

 tains an account of the Upper and Middle Silurian series, while the 

 eighth describes the Lower Silurian series, of which the Quebec group 

 is the most important. Of this the author says : — " Not only is the 

 Quebec group the great metalliferous formation of North America, 

 but its remarkable thickness (7000 feet) and complexity, coupled 

 with the extraordinary manner in which it was deposited and brought 

 to the surface, all unite to make it one of the most interesting and 

 important formations of the entire geological series, with perhaps the 

 single exception of the Coal-measures. Not only does it comjDrise a 

 great variety of useful rocks, but it contains in remunerative quan- 

 tities iron, copper, nickel, cobalt, antimony, lead, zinc, chromium, 

 arsenic, titanium, silver, and gold." There are some interesting re- 

 marks respecting the chemical origin of the metals of the Quebec 

 group, taken from Professor Hunt's work ' On some points of 

 American Geology,' in which it is suggested that they were originally 

 brought to the surface in watery solutions, from which they were se- 

 parated by the reducing agency of organic matter in the form of sul- 

 phurets, or in the native state, and mingled with the contemporaneous 

 sediment in various forms. The intervention of intense heat, subli- 

 mation, and similar hypotheses, to explain the origin of metalhc ores 

 is considered to be uncalled for, and reference is made to the beau- 

 tiful experiments of De Senarmont and Daubree. The different de- 

 velopments and contents of the Quebec group are more fully described 

 in the ninth chapter. In the following chapter much information 

 will be found respecting the effects of glacial action in modifying the 

 surface of the country, in many parts of which boulders of great size 

 and in considerable quantities are found. The rocks, too, are every- 

 where scratched, striated, and polished. In accounting for these 

 phenomena, Mr. Hind gives the preference to the theory of a glacial 

 covering rather than to the iceberg theory. A comparatively slight 

 elevation of the country, rising gradually to the north, would account 

 for all these phenomena by the theory of a glacial covering more 



