MINERALOGICAL QUERIES. 115 



several miles. Are these masses to be considered 

 as true beds, or veins parallel with the direction 

 of the strata ? 



12. What are the geognostic characters and 

 relations of the porphyri tic- rock of the Ochil- 

 hills ? 



As far as I can judge, from that portion of the 

 range of the Ochils I have examined, this rock 

 appears to belong to the same formation as the 

 clay stone and felspar of the Pentlands. 



13. What is the extent and mode of distribu- 

 tion of the granite and sienite of Galloway ? 



In Galloway, I found both the sienite and what 

 appeared to be the newest granite formations, but 

 had not ieisurj^to ascertain the geognostic rela- 

 tions of anotlwPgraiiite which appears to belong 

 to the oldest formation. 



14. Does the upper part of Ben Nevis belong 

 to the second porphyry formation ? And if 

 so, on what rock does this porphyry rest ? 

 And does not the granular rock found in this 

 mountain, rather belong to the sienite than 

 to the oldest granite formation ? 



From specimens of that mountain, which I 

 have had an opportunity of examining, its upper 

 part appears to be composed of a dark- coloured, 

 nearly greyish-black 5 porphyry ; its lower parts 



If 2 



