r 616 ] 



XXXIV. Analysis of Compact Felspar from 



Pentland Hills. 



By Charles Mackenzie, M. D, 



[Read %teh November 1810.] 



The country around Edinburgh, in a mineralo- 

 gical point of view, is one of the most interesting 

 in Scotland. No fewer than three of the univer- 

 sal formations occur within a few miles of the 

 city, namely, transition, oldest coal, and newest 

 Jicetz trap. Much of the lower and flatter part of 

 the country is occupied with coal and newest Jicetz 

 trap formations ; but the higher parts contain, 

 besides these, considerable portions of transition 

 rocks. The Pentland Hills, from which the fel- 

 spar that forms the subject of this paper was ob- 

 tained, constitute the highest ground near Edin- 

 burgh, rising in some places, Loganhouse Hill, for 

 example, to the height of 1700 feet above the 

 level of the sea. This elevated tract, according 

 to the examination of Professor Jameson, contains 



