MINERALS OF THE ARCHAEAN. 61 



tion, now in another, ranging freely between the limits of northeast and 

 northwest. 



In the study of the Archaean slates and schists the absence of the 

 numerous minerals so abundantly found in the metamorphic slates and 

 schists of the East is peculiarly worthy of remark. With the exception of 

 garnet, crystallized mica, and hornblende, and in the micaceous schists of 

 the western series the rare staurotide, epidote, and graphite, none of the 

 common silicated minerals were met with. Excepting the brown hematite 

 of the oxidized silicious veins or strata and the specular hematite of the 

 slates, the metallic minerals were rarely obtained from indigenous rocks. 

 Galena is said to have been found at one place on Castle Creek, but that it 

 is not a common mineral is proven by the entire absence of any particles in 

 the drift or gravel. Pyrites, as a portion of vein matter, was found in several 

 localities, and though at present not largely found it probably was once 

 widely distributed in the veins and seams, the oxidation of which has con- 

 verted it superficially to the brown oxide of iron. Mispickel has also been 

 found in the same association. 



Gold, originating undoubtedly in the quartz seams, is now found in the 

 gravel and drift of the valleys and in the basal portions of the Potsdam, 

 and though there are doubtless many of the seams that carry the gold in 

 a free state, it is so fine and so sparsely disseminated that gold-bearing 

 rock with visible particles is rarely met with. The wearing down of the 

 rocks and the concentrating action of waves and currents have nevertheless 

 so sifted out and accumulated the precious metal, that in many places it is 

 now found in tolerable abundance in the ancient and modern gravels. 

 Quartz seams are so abundant that if they were all, or the larger part of 

 them, auriferous, the quantity of gold in the gravels would be much larger 

 than it is actually found. 



No fossils were found in the Archaean rocks ; and marble and serpen- 

 tine, the metamorphic rocks most likely to yield them, were not seen. 



Our examination brought to light no evidence of the duplication of any 

 parts of the Archaean rock system. If the slates or the schists were folded 

 upon themselves and afterwards worn away so as to leave two or more par- 

 allel outcrops of the same beds, the folding must, have been confined to the 



