INDUSTRIAL PROGRESS DURING THE YEAR 1872. xxxiii 



has been that of the existence of tin, in immense quantity, 

 in Queen's Land, and extending over so large an area, and in 

 such richness of percentage of the metal, as to promise a 

 very large addition to the resources of the world as regards 

 this substance. The alleged discovery of tin ore on the 

 shores of Lake Superior is now pronounced to be entirely 

 false. 



The increased demand for mica has resulted in the devel- 

 opment of new mines in North Carolina ; and in connection 

 with this have been found large deposits of corundum, some- 

 times in immense masses. Owing to various causes, partly 

 the anticipation of a future scarcity, and partly to combina- 

 tions of capitalists, the price of coal has gone up to a rather 

 high figure in England, which is involving important changes 

 in manufactures and their export, as far as Great Britain is 

 concerned, in consequence of the increased price of iron and 

 most other articles. This has naturally redounded to the 

 benefit of the manufacturing interest of the United States. 



In American Geology, much new light has been thrown 

 upon the history of the Palaeozoic strata, which make up so 

 large a part of the rocks east of the Rocky Mountains. The 

 question as to the age of the copper-bearing strata of Lake 

 Superior has long been one in dispute; for while Hall, Whit- 

 ney, Logan, and many others had claimed them to belong 

 to the lower part of the palaeozoic series, there were not 

 wanting; those who asserted their mesozoic a<je. This was 

 grounded on the lithological resemblances between these bed- 

 ded amygdaloidal traps, as they were called, with rocks be- 

 longing to that period in Europe and in eastern North Amer- 

 ica. Now, although certain crystalline strata of aqueous or- 

 igin may, and doubtless do show such characteristics that 

 their geological age and sequence may be determined from 

 their general mineralogical composition, this can scarcely be 

 looked for in rocks which, like the copper-bearing traps of 

 the Keweenaw series, are eruptive in their, origin. The late 

 researches of Brooks and Pumpelly seem to show conclusive- 

 ly that the copper-bearing traps of Keweenaw are a very 

 ancient series, and lie unconformably beneath the nearly hor- 

 izontal sandstones of the vicinity, which occupy a position 

 beneath the Trenton limestone of the New York series. 

 This limestone, with its characteristic fossils, is, in fact, found 



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