Page:Transactions of the Geological Society, 1st series, vol. 3.djvu/268

 paper the aspect of a controversial essay, rather than of that to which it alone pretends, a descriptive one; for which reason I have chosen to describe it precisely as it appeared to me. Where my description differs from that of others, the differences will be found to consist at times in a difference of opinion respecting the denominations of rocks, while on other occasions they are much too great to admit of their arising from a different use of the same terms, or a different mode of contemplating the same phenomena; they are differences respecting facts, and are therefore the less fit subjects of discussion.

As the local circumstances which require to be examined before an adequate notion can be formed of the true structure of this interesting place occupy a considerable range of country, and as inevitable confusion would follow any attempt to describe the mineral beds and their geological connections in their natural order, on account of their perpetual interference with the geographical disposition of the ground, I have chosen to adopt a geographical method. In so doing I shall the more readily be understood as far as the simple specification of facts goes, and those who shall incline to follow me in the investigation of this spot will also be furnished with a clue by which they may trace the description, and the more easily confirm or refute, as it may happen, that which I shall relate. In the present state of geological knowledge, this method of proceeding seems absolutely necessary. Like the detail of chemical experiments it enables the reader to follow step by step the appearances from which the general results have been deduced, to examine the inferences as they are drawn from the phenomena, and finally to determine on the legitimacy of the conclusion. Such inferences or such general conclusions, as appear to me to result from a comparison of these facts duly approximated, will be stated afterwards.