298 SCIENCE PROGRESS 



lack of quantitative data has rendered this study indecisive, 

 but Prof. Gregory shows that by far the greater amount of 

 gravel is yielded by the continental agencies, rivers and glaciers, 

 whilst marine action yields relatively little. 



An account of the geology of the island of South Georgia 

 is given by D. Ferguson, Prof. J. W. Gregory, and the writer 

 {Trans. Roy. Soc. Edin. 191 5, L, 797), based on observations 

 and collections made by the first-named author. The island 

 consists of an extensive sedimentary series, mainly arenaceous 

 in character, but with a considerable development of argilla- 

 ceous types, and bedded trachytic tuffs, which have undergone 

 sporadic scapolitisation. The evidence of the few crushed and 

 fragmental fossils as to the age of the rocks is ambiguous, 

 and appears to show that a single well-knit formation, the 

 Cumberland Bay Series, is probably Lower Palaeozoic in its 

 basal, and Mesozoic in its upper beds. The facts are not 

 sufficient for the authors to pronounce definitely on the tec- 

 tonic relations of the island ; and the question whether it 

 belongs to a great loop, the so-called " Southern Antilles " of 

 Suess, connecting the Andes with Graham Land, or whether it 

 is a remnant of Prof. Schwarz's old southern continent of 

 Flabellites Land, is left open pending the collection of new facts. 



The Canadian Geological Survey publishes a memoir (No. 6y) 

 by D. D. Cairnes, on the Yukon- Alaska International Boundary 

 between the Porcupine and Yukon Rivers. The boundary 

 traverses a mountainous region which is built mainly of sedi- 

 ments forming one of the most complete Palaeozoic sections 

 yet known in the North American Cordillera. Another Cor- 

 dilleran area is described by C. W. Drysdale in a memoir (No. 

 56) on the geology of the Franklin Mining Camp, British 

 Columbia. Here the great Mesozoic batholiths appear, also a 

 later series of alkaline rocks {postea, under Petrology), intruded 

 respectively into Palaeozoic and Cainozoic sediments. 



Petrology- Igneous Rocks. — J. P. Iddings and E. W. Morley 

 {Jour. Geol. 191 5, 23, 231) describe the leucitic lavas of Mount 

 Mouriah in Java and the shonkinites and nepheline-syenites 

 of the Pic de Maros in Celebes. The first-named group includes 

 vicoite, leucite-tephrite, leucitophyre, and shoshonite lavas. 

 The Celebes locality exhibits several varieties of shonkinite, 

 including one rich in biotite and augite which is called marosite. 

 Nepheline-syenites, with syenite-porphyry, bostonite, trachyte, 



