322 Notices of Memoirs. 



11. — NoDULAB Granite from Pine Lake, Ontario. By Frank 

 Dawson Adams, Ph.D. (Bulletin of the Greological Society of America, 

 1897, vol. ix, pp. 163-172, pi. xi ; February 10, 1898.)— Professor 

 Adams, while carrying out some work for the Geological Survey of 

 Canada in the eastern part of the Province of Ontario, has discovered 

 a remarkable occurrence of orbicular or nodular granite in the 

 township of Cardiff, in the county of Peterborough. In this part 

 of the country the fundamental rocks are Crystalline Limestones, 

 associated with Gneisses and Amphibolites, broken through by great 

 intrusions of Granite. The nodule-bearing Granite occurs on the 

 north and south sides of Pine Lake. It is rather fine-grained and 

 usually gneissic in places, but often massive. The nodules are 

 confined to a portion only of the Granite, and are not in proximity 

 to the Amphibolite ; and therefore the nodular structure is not 

 a contact phenomenon. The nodules are spherical or ellipsoidal, 

 and occur either scattered through the rock or, more rarely, in 

 lines. When the nodules occur in rows they gradually get closer 

 together until they seem to fuse or coalesce into a continuous band 

 or vein. The centres of the nodules exhibit little segregation 

 bunches of schorl. Professor Adams concludes that these nodules 

 are due to a primary differentiation of the magma, for the reason 

 that they do not include certain minerals such as Microcline, which 

 have evidently crystallized from the magma latest, and which are 

 abundant in the surrounding Granite ; while on the other hand Silli- 

 manite occurs in the nodules, being one of the first to separate from 

 the magma, but does not occur in the surrounding Granite. — F. C. 



III. — An Experimental Investigation into the Flow of 

 Marble. (Philosophical Transactions of the Eoyal Society of 

 London, 1901, vol. cxcv, pp. 363-401.) — These experiments have 

 been carried out by Messrs. Frank Dawson Adams and John Thomas 

 Nicolson ; pure Carrara marble being the rock selected. The paper 

 deals with the methods employed, deformation of the dry rock at 

 ordinary temperature, at 300 C, and at 400 C, and at 300 C. in the 

 presence of water. Comparison is made of the structures produced 

 in Carrara marble by artificial deformation with those produced by 

 deformation in the case of metals, and comparison of the structures 

 produced with those observed in the limestones and marbles of 

 highly contorted portions of the earth's crust. The following is 

 the summary of results : — (1) By submitting limestone or marble 

 to differential pressures exceeding the elastic limit of the rock 

 and under the conditions described by the authors, permanent 

 deformation can be produced. (2) This deformation, when carried 

 out at ordinary temperatures, is due in part to a cataclastic structure 

 and in part to twinning and gliding movements in the individual 

 crystals composing the rock. (3) Both of these structures are seen in 

 contorted limestones and marbles in nature. (4) When the deforma- 

 tion is carried out at 300 C. or, better, at 400 C, the cataclastic structure 

 is not developed, and the whole movement is due to changes in the 

 shape of the component calcite crystals, by twinning and gliding. 

 (5) This latter movement is identical with that produced in metals 



