420 Mino'alogical Olservations in Galloivuy. [June, 



ness in a small retort connected with a pneumatic apparatus. The 

 gas evolved was pure oxygen gas. Hence 100 parts of black oxide 

 of manganese are composed of 



Metal 7 1 -.33 



Oxygen 28-67 



100-00 



Article III. 



Mineralogkal Olservations in Galloway. By James Grierson, 

 M.D. Read before the VVeruerian Society, March 6, 1814. 



(With a Map.) 



It is now I believe known to every mineralogist, of this country 

 at least, that three distinct masses of granite occur in the transition 

 district which principally constitutes the two counties of Galloway : 

 the westernmost, or Loch Doon mass ; the middle, or Dee mass; 

 and the easternmost, or Criffle mass. These are nearly of equal 

 sizes, and include each a space of about eight or ten miles by three 

 or four. The Loch Doon and Criffle masses I have not had an 

 opportunity of examining ; but the middle, or Dee one, has at 

 different times occupied my attention. The granite in each of 

 these three districts appears to be in no part of its boundaries at a 

 great distance from the transition rocks, viz. greywacke and grey- 

 vvacke slate, of which by far the greater part of the counties of 

 Galloway is composed. 



The Dee granite district extends from within about two miles of 

 the borough of New Galloway, on the north, to within nearly the 

 same distance of Creetown, on the south., or to the bay of Wigton, 

 at the mouth of the river Cree. It includes the following hills, 

 which rise to a considerable height : Blackcraig, Cairn Edward, 

 Louran, Hill of Orchar, Hill of Airy, Hill of Kittrick and 

 Cairnsmuir, which last is considerably higher than any of the rest, 

 and rises to 17^7 feet above the level of the sea. The bounding 

 line of the granite may be sketched in the following manner. It 

 touches Lich Ken, two miles S. S. E. of New GallowuV, continues 

 to run along the brink of that lake for a mile and a half souih, then 

 passes a little mere to the westward, a short way above the house of 

 Bennan, and stretches away with no very great variety of direction 

 to the hill of Sloughary, and across to the river Fleet. It then 

 makes a gradual turn to the westward, round by Creetown, up the 

 Burn of Palnure, past Craigdews, and by the high bridge of Dee, 

 round the west side of Blackcraig, down by Nocknairland, about 

 two miles south of New Galloway, and into the lake of Ken. This 



