Vol. 60.] METAMORPHISM IN THE LOCH-LOMOND DISTRICT. 29 



the crystalline schists and less-altered sedimentary rocks. It was felt 

 that, until a much larger area of the Highlands had been mapped and 

 some more distinctive stratigraphical horizons had been traced, no 

 definite conclusions on the subject could be drawn. The fresh in- 

 formation required had been now supplied by the work of the Author. 

 Using the horizon of the ' Green Beds ' as the key to the structure of 

 the ground, he had shown that the apparently-enormous thickness of 

 the rocks could be satisfactorily reduced to much more reasonable 

 proportions, and that folding on a great scale had affected the whole 

 region. With the microscope as an adjunct to his field-work, the 

 Author had been able to trace an interesting series of metamorphic 

 changes, from the coarse grits of the Highland Border into highly- 

 crystalline albite-gneisses. He was about to proceed to the West 

 Indies to undertake some important duties there, and the speaker 

 was sure that the Society would heartily wish him all success in 

 that distant region, and would hope to welcome him on his return 

 with a fresh harvest of geological results. 



The Author, in answer to Mr. Cadell, said that the limestone in 

 the Aberfoil Slates was not the same as the limestone occurring to 

 the north, which was the Loch-Tay Limestone, at a much higher 

 horizon. The contact-metamorphism had not been examined in 

 detail, nor had the source of the ilmenite in these schists been 

 ascertained. As the Chairman had said, it was the mapping of the 

 ' Green Beds ' which had explained the structure of the district and 

 indicated the thickness of the rocks. He thanked the Chairman 

 for his remarks, and the Fellows for the manner in which the paper 

 had been received. 



