478 APPENDIX. 



A knowledge of mineralogy forms the very founda- 

 tion of this science, often as that is forgotten ; since, 

 without it, the geologist will never acquire a ready and 

 accurate knowledge of rocks, independently of the 

 other demands on him which it possesses. There are 

 also numerous appearances in geology, which I need 

 not now enumerate, on which he will never reason 

 justly without this knowledge ; as the facts will even 

 escape the notice of him who is, thus far, without eyes: 

 while it might be invidious to notice the gross errors 

 to which mineralogical ignorance has often given rise. 

 Geology and mineralogy are indeed but two branches 

 of a common science ; while if discoveries in the latter 

 must originate with the geologist, it is certain that 

 these will be proportioned to his previous knowledge. 

 If, with the botanist, not versed in the principles that 

 distinguish their respective objects, the treasures of 

 nature will pass before each, unnoticed and unknown. 

 Nor can we place much confidence in him who pre- 

 tends to distinguish among complicated and difficult 

 appearances, when he has proved his deficiency in a 

 subject of far easier attainment. 



It is almost superflous, after this, to say, that a mi- 

 nute and ready knowledge of rocks is indipensable. It 

 would be endless to repeat the cases in which it is in 

 perpetual requisition, and the errors which have arisen 

 from the want of it; though I may allude to the con- 

 fusion of former geologists respecting pitchstone and 

 jaspers, hornblende schist and trap, granite and quartz 

 rock, with the pernicious conclusions and permanent 

 ignorance to which these have given rise. Nor have 

 we a right to suppose that all the rocks in nature are 

 known. Quartz rock, hypersthene rock, augit rock, 

 compact felspar, chert, and more, have been added, by 

 my own researches, to a list not long ago deemed com- 



