374 SCIENCE PROGRESS 



remarkable for an outspoken condemnation of the practice of 

 using a common nomenclature for the huge Pre-Cambrian 

 region of the St. Lawrence basin, when only a small part of it 

 has been surveyed in any detail. Especially misleading is the 

 widespread use of the term Keewatin for all occurrence of 

 schistose basic volcanic rocks apparently at the base of the 

 Pre-Cambrian succession, with the implication that these are 

 all of the same age. The author also believes that there are at 

 least three periods of batholithic intrusion in the Canadian 

 Shield ; thus the vexed question of Pre-Cambrian correlation 

 becomes more complicated than ever. Mr. Wilson returns to 

 this subject in a separate paper (Journ. Geol. 191 8, 26, 325-33)^ 



Coleman, A. P., Permo-Carboniferous Glacial Deposits of 

 South America, Journ. Geol. 191 8, 26, 310-24. (Describes 

 three widely separated areas of tillite in Brazil and Argentina.) 



Kirk, E., Palaeozoic Glaciation in South-eastern Alaska, 

 Amer. Journ. Set. 191 8, 46, 511-15. (Describes Silurian and 

 Permian glacial deposits.) 



The Tuapeka district (New Zealand), described by P. 

 Marshall (Geol. Surv. New Zealand, Bull. No. 19, 191 8, 79 pp.) 

 is part of the main folded axis of the South Island of New 

 Zealand. It consists principally of Pre-Jurassic greywackes 

 and schists, followed unconformably by an auriferous con- 

 glomerate of Upper Cretaceous or Lower Eocene age. This 

 district was formerly the chief gold-field of New Zealand. 



Thomson, J. A., Diastrophism and Other Considerations in 

 Classification and Correlation, and the Existence of Minor 

 Diastrophic Districts in the Notocene, Trans. N.Z. Inst. 191 7, 

 49, 397-4I3- (Diastrophism discussed in relation to New 

 Zealand stratigraphy.) 



Petrography. — Dr. A. Holmes has described a collection of 

 basaltic rocks from the Arctic regions (Greenland to the Yenesei) 

 with the aid of nine full chemical analyses by Dr. H. F. Har- 

 wood (Mineral. Mag. 191 8, 18, 180-223). He shows that the 

 Brito-Arctic petrographic province is composite, and that it is 

 characterised by basaltic rocks which show a regional variation 

 in composition. In the olivine-free basalts consanguinity is 

 mainly indicated by an antipathetic relation between felspars 

 and titania. There is a well-marked geographical distribution 

 of the last-named constituent. The basalts of the partly 

 submerged North Atlantic ridge, which includes South Green- 



