1889.] Contact Metamorpliism in Silurian Rocks. 



193 



was seemingly due to the magnetic poles diversely influencing the 

 action of the solution on the metal ; and in the case of the copper 

 salts, the ratio of the electro-deposition of the copper was apparently 

 affected by these magnetic influences. It may be remarked that this 

 research has been replete with difficulties of various kinds, and about 

 386 magnets have been experimented upon in Part III with the 

 various solutions to endeavour to ensure accuracy in the observations 

 recorded. 



II. (i Report on the Effects of Contact Metamorpliism exhibited 

 by the Silurian Rocks near the Town of New Galloway, 

 in the Southern Uplands of Scotland." By S. Allport, 

 F.G.S., and T. G. Bonnet, D.Sc, F.R.S.* Received May 7, 

 1889. 



In the ' Transactions of the Royal Society of Edinburgh ' (vol. 7, 

 p. 79) is a paper by Sir John Hall, in which he says that he read 

 to that Society, in the year 1790, an account of his observations on 

 the granitic mass of Loch Ken. In this he stated that in all the 

 " extent where the junction of the granite with the schistus was 

 visible, veins of the former, from 50 yards to the tenth of an inch in 

 width, were to be seen running into the latter in all directions, so 

 as to put it beyond all doubt that the granite of those veins, and 

 consequently of the great body itself, which I observed forming with 

 the veins one continuous and uninterrupted mass, must have flowed 

 in a liquid state into its present position." 



Of the accuracy of these observations no competent observer can 

 entertain a doubt, and microscopic examination of the rocks invaded 

 reveals the great structural and mineralogical changes which have 

 been produced by the intrusive granite. The portion of the altered 

 Silurian strata examined by Mr. Allport forms a narrow band 

 between the margin of Loch Ken and the granite massif of Cairn 

 Muir and Cairn Fleet on the other. Starting from Lochside Point 

 (about 2 miles south of New Gralloway), and following a line drawn 

 along the west side of the loch in a northerly direction, the altered 



# The origin and authorship of this communication should perhaps be explained. 

 In 1880 a grant was made by the Royal Society to Mr. S. Allport to enable him to 

 study the phenomena of contact metamorpliism in southern Scotland. Shortly 

 before going there, he received an appointment at Mason's College, Birmingham, 

 which for a while took up his whole time ; and then a severe illness obliged him 

 to lay aside for many months all scientific work. Last autumn, being still far from 

 strong, he consulted me as to the best way of indicating that the above-named grant 

 had not been without fruit, and, after some consideration, it was arranged that I 

 should work over his specimens, and embody his notes with my own impressions in 

 a report to the Royal Society. — T. Gr. B. 



