TRANSACTIONS OF SECTION C. 615 



Section C— GEOLOGY. 

 President or the Section — John PIorne, F.E.S., F.R.S.E., F.G.S. 



THURSDAY, SEPTEMBEB 11. 

 The President delivered the following Address : — 



Recent Advances in Scottish Geology. 



A quarter of a century has elapsed since the British Association met in this 

 preat industrial centre, when Professor Young, in his presidential address to this 

 Section, pointed out some of the difficulties which, as a teacher, he experienced in 

 summarising the principles of geology for his students. At that meeting, also, the 

 late Duke of Argyll, whose interest in geological questions never faded, gave an 

 address ' On the Physical Structure of the Highlands in connection with their 

 Geological History,' The return of the Association to the second city of the 

 empire, which since 1876 has undergone remarkable development, due in no small 

 measure to the mineral wealth of the surrounding district, suggests the question. 

 Has Scottish geology made important advances during this interval of time ? 

 Have we now more definite knowledge of the geological systems represented in 

 Scotland, of their structural relations, of the principles of mountain-huildiug, of 

 the zonal distribution of organic remains, of the volcanic, plutonic, and meta- 

 morphic rocks so largely developed within its borders? It is true that many 

 problems still await solution, but anyone acquainted with the history of geological 

 research must answer these questions without liesitation in the affirmative. In 

 tlie three great divisions of geological investigation — in stratigraphical geology, in 

 paleontology, in petrology — the progress has indeed been remarkable. The details 

 of these researches are doubtless familiar to many who have taken an active share 

 in the work, but it may serve a useful purpose, and perhaps be helpful as a land- 

 mark to give now an outline of some of the permanent advances in the solid 

 geology of Scotland during the last quarter of a century. 



The belt of Archtean gneisses and schists, which may be said to form the 

 foundation stones of Scotland, have been mapped in great detail by the Geological 

 Survey since 1883 along the western part of the mainland in the counties of 

 Sutherland and Ross. In that region they occupy a well-defined position, being 

 demonstrably older than the great sedimentary formation of Torridon Sandstone 

 and overlying Cambrian strata. The mapping of this belt by the survey stafi" and 

 the detailed study of the rocks both in the field and with the microscope by Mr. 

 Teall have revealed the complexity of the structural relations of these crystalline 

 masses, and have likewise thrown considerable light on their history. These 

 researches indicate that, in the North-west Highlands, the Lewisian (Archtean) 

 gneiss may be resolved into (1) a fundamental complex, composed mainly of 

 gneisses that have affinities with plutonic igneous products, and to a limited extent 

 of crystalline schists which may without doubt be regarded as of sedimentary 



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