PREFACE. xiii 



out leaving the subject in darkness, they have been 

 introduced. I must not however terminate this part of 

 the subject without noticing Professor Jameson's work 

 on the same tract of country. I would willingly have 

 shortened my own labour by being indebted to it, and 

 am glad to bear testimony to the accuracy of his ac- 

 count, as far as the facts have been described. The 

 difference of the plan on which this survey was con- 

 ducted, rendered it necessary to examine every thing, 

 and deprived me of the assistance which I might 

 otherwise have derived from that work ; which in- 

 cludes, moreover, but a small portion of the territory 

 which has here been investigated. 



If the following descriptions should sometimes 

 appear unnecessarily minute, and therefore prolix, 

 it must be recollected that a merely topographical 

 account would contribute nothing towards geological 

 science. That science remains yet to be created ; 

 and the facts that are to be collected towards it, 

 must be viewed in the manner which our present 

 conjectures as to their eventual utility may suggest 

 as prospectively most conducive towards that leading 

 object. When geological analogies and relations shall 

 become thoroughly understood, a work on mineral 

 topography will be comparatively brief, and may 

 admit of being superficial. It is moreover impos- 

 sible, in the present state of the science, to foresee 

 the utility of minute research, or the serious defi- 

 ciencies which may hereafter be found to arise from 

 the neglect of circumstances apparently trifling. The 

 classical naturalists doubtless imagined that they had 

 given descriptions by which the objects of their 

 investigations could be for ever recognised. Our 



