LOCH DOON DISTRICT. 153 



grey wacke, and traverses the latter in numerous veins. The 

 grey wacke is intimately connected with the granite at the 

 junction ; but there is no transition into any rock which 

 can with any degree of propriety be referred to the primitive 

 series of the Wernerian geognosy. The granite which occurs 

 here is a compound of a yellowish- white felspar with the ac- 

 companying minerals of quartz and mica. Another locality 

 which we examined for the purpose of noticing thealtering ef- 

 fects of granite was at the old bridge of Dee, about half a mile 

 to the south of Clatteringshaws toll-bar. The greywacke 

 here is indurated, but it is still greywacke, and abuts at a 

 considerable angle against the granite which has upraised it. 



III. Loch Doon District* 

 The third granite group, which is associated with the strata 

 of the south of Scotland, is that of the district of Loch Doon ; 

 and as connected with that metamorphic theory, which sup- 

 poses that the gneiss and mica-slate strata are only altered 

 sandstones and shales, the junctions exhibited in this quarter 

 are interesting. To trace the connections of granite with its 

 associated strata, and to examine the appearances observable 

 at their junctions, has long been an object of geological inves- 

 tigation. In the generality of cases, however, this examina- 

 tion can only be made in regard to the contact of granite 

 with rocks which, though stratified, are nevertheless a com- 

 plete crystalline aggregate, and bear impressed upon them 

 characters as completely indicative of a consolidation from a 

 state of fluidity as the unstratified granitic masses which oc- 

 cur among them. If we wish to discover, therefore, whether , 

 such rocks have lost their original mechanical characters by 

 the action of the granite, it is evident that we must endea- 

 vour to find an indubitable mechanical rock so connected with 



• Vide Dr Grierson's Memoir on the " Mineralogy of Galloway," in 

 vol. ii. Mem. Wern. Soc, for his description of the granite and grey- 

 wacke junctions in this district. 



