PRIMARY GEOLOGY CHAPTER I. Introduction : —reasons for undertaking this work — the nature of its contents — its objects twofold. — The study of the primary rocks long neglected — beginning to attract more attention. — The proposed order of arrangement. The discussion of geological opinions, which are professedly hypothetical, and which can only be expected to enjoy an ephemeral existence, in consequence of the rapidly progres sive state of the science, may appear to many to be an unpro fitable occupation of time, which might be better employed in the examination and description of the phenomena of nature. But it will, perhaps, be more generally admitted that such speculations are conducive to the welfare of the science, by promoting and directing various investigations, and by ex citing the geologist to greater exertions during his toilsome excursions. By such an admission, however, it is not intended to advo cate the labours of the mere theorist, whose knowledge has been entirely derived from books; but, to contend for the utility of such theoretical views as have been deduced from practical experience. Having, therefore, observed, during a geological survey of Cornwall, many facts which appeared to be incompatible with the prevailing theory, I was induced to publish them in the “ Cornish Transactions,” and to attempt their solution by an other explanation.