I. Introduction. The detailed mapping of the eastern portion of the County of Sutherland by the Geological Survey has shown that the crystalline schists of that region are extensively penetrated by granites, more or less foliated, which are apparently linked to some extent with the present crystalline characters of these schists. Some of the features presented by these foliated granites have already been described by previous observers. In 1862 Prof. Harkness remarked that the mode of occurrence of the granites in the east of Sutherland rather tends to the conclusion that the sedimentary rocks were elevated, flexured, and contorted previous to the period when the granites made their appearance in the sedimentary rocks, and that these granites have conformed in their course to the strike of the previously elevated strata. He further observes that here are abundant features which would support the conclusion that granite is in this district rather the result of an excessive amount of metamorphic action than a plutonic rock as regards its origin. In 1869 the Rev. Dr. Joass stated that he was inclined to regard the granites in the Kildonan region as partly intrusive and partly metamorphic. He further noted that in the most richly auriferous localities certain granitoid rocks, chiefly felspathic, are so intimately connected by interlamination with the flaggy quartzose strata that they almost appear to be the result of metamorphic action upon true sedimentary rocks of the quartzose series, or contemporaneous effusions of plutonic rock. This granitiform rock appears at least in