Reports & Proceedings — Geological Society of London. 185 



Since the spilites appear to be differentiates from a normal basaltic 

 magma, resulting largely from their physical environment, it is 

 concluded that they do not form a separate suite of igneous rocks 

 distinct from other alkaline rocks. 



Annual General Meeting. 



2. February 16, 1917.— Dr. Alfred Harker, F.R.S., President, in 



the Chair. 



The reports of the Council and the Library Committee were read. 

 It was stated that 34 Fellows were elected in 1916 (3 more than in 

 1915). During the same period, the losses by death, resignation, and 

 removal amounted to 66, the actual decrease in the number of 

 Fellows being 32. The total number of Fellows on December 31, 

 1916, was 1231. 



The balance-sheet for that year showed receipts to the amount of 

 £2,668 3s. Id. (excluding the balance of £635 13s. Ad. brought 

 forward from 1915) and an expenditure of £2,627 4s. 



Reference was made to the decease of the Treasurer, Mr. Bedford 

 McNeill, and to the election, in his place, of Dr. J. V. Elsden. 



The awards of the various Medals and Proceeds of Donation Funds 

 in the gift of the Council were enumerated in the Geological 

 Magazine for March, 1917, p. 140. 



The Reports having been received, the President handed the 

 Wollaston Medal, awarded to Professor Antoine Frangois Alfred 

 Lacroix, F.M.G.S., to Sir Archibald Geikie, O.M., for transmission to 

 the recipient, addressing him as follows : — 



Sir Archibald Geikie, — For a Medal instituted "to promote researches 

 concerning the mineral structure of the Earth" it would be difficult to find 

 a fitter recipient than Professor Lacroix, to whose labours in the domain of 

 mineralogy and petrology our science is so deeply indebted. His researches 

 on the optical and crystallographic constants of numerous minerals have 

 given us a mass of useful data ; but it has always been his practice to 

 extend his investigations to the field as well as to the laboratory. His 

 studies of the mode of occurrence, the mutual associations, and the 

 manner of origin of a host of species have done much to rehabilitate 

 mineralogy as, not merely a department of physics and chemistry, but 

 a fascinating branch of natural history. His many separate papers deal 

 with material from all parts of the world ; but of chief importance will 

 always be reckoned his four volumes on the mineralogy of France and her 

 Colonies, a single-handed work unique in its wide scope and comprehensive 

 treatment. 



In petrology, too, Professor Lacroix's contributions have been numerous 

 and many-sided. Of special note for their influence upon the science are 

 his researches on contact-metamorphism, contained in bulletins of the 

 Geological Survey of France, his various memoirs treating of the inclusions 

 in igneous rocks, and his comparative study of the volcanic products of 

 Mont Pele, followed by a like examination of the rocks of Vesuvius. 



From the products of volcanoes to the physics of volcanic action is 

 a natural transition, and in respect of both Professor Lacroix's mission to 

 Martinique in 1902 was eminently fruitful in results. In particular he was 

 able to elucidate two remarkable phenomena previously unrecognized or 

 unappreciated, the peculiar plugs or domes formed under certain conditions 

 by extruded lavas and that most terrible of all volcanic effects, the nude 

 ardente. 



