various parts of Scotland. 391, 



cumlocutlon which it would be desirable to avoid, yet till either a 

 system is firmly established on a wide and fair induction, or a set of 

 terms can be produced independent of all system, such circumlocution 

 is perhaps inevitable. 



I have only to add, that since the following remarks did not admit 

 of any useful or methodical arrangement, they are placed with little 

 regard to order, and as the subjects of them occurred. That they 

 are so detached, and often so superficial, must be imputed partly to^ 

 want of knowledge, partly to want of time, and still more to the 

 uncontroulable elements, to which the best laid projects of the rame- 

 ralogist as of the husbandman must bend» 



Rona, 



I should scarcely have introduced any remarks on Rona, were it 

 not for the purpose of mentioning that wolfram, hitherto unnoticed, 

 in this spot, is found in the granite veins that traverse the gneiss 

 of which this island is principally formed. I may however re- 

 mark at the same time, that these veins exhibit that variety of 

 granite called graphic, a rock of much more frequent occurrence 

 than it was once supposed. The graphic granite of Rona is dis- 

 tinguished by the great size of the crystals of felspar which enter 

 into its composition, and consequently by the equal magnitude and 

 distinctness of the quartz which fills their intervals. An accurate 

 survey of Rona is still a desideratum for future mineralogists, as the 

 number, magnitude, and peculiar character of the granite veins might 

 give us hopes of detecting in them some of the rarer minerals knowrv 

 to be inmates of such veins, and observed in similar situations ia 

 other parts of the earth. I cannot however dismiss this subject of 



