570 SCIENCE PROGRESS 



Corals from Central America, Cuba, and Porto Rico, with an 

 Account of the American Tertiary, Pleistocene, and Recent 

 Coral Reefs " (Smithson. Inst., U.S. Nat. Mus. Bull., 191 9, 103, 

 189-524), which is further notable as containing a full state- 

 ment of Vaughan's views on coral-reef formation, to be dealt 

 with more fully in forthcoming notes. 



Aequinoctia is the name given by Abendanon (Journ. Geol., 

 1 919, 27, 562-78) to an old Palaeozoic continent which ex- 

 tended over 45 degrees of latitude between South-east Asia and 

 the east of Australia. The remains of its nucleus of Archaean 

 and Pre-Cambrian rocks are to be found in many of the East 

 Indian Islands. The dismemberment of this continent began 

 in the Permo-Carboniferous, and continued during the Mesozoic 

 and Tertiary. 



Falklandia is a name applied by Clarke (Proc. Nat. Acad. 

 Sci., 19 1 9, 5, 102-3) to a continental land which existed in the 

 occidental parts of the Southern Hemisphere during the 

 Devonian period, and preceded Gondwanaland and Antarctis. 

 The Devonian of these latitudes is a unit both in life and in 

 sedimentation. Falklandia traverses part of Schwarz's Flabel- 

 lites Land, which name is superseded for no very clear reason. 



Dr. W. Howchin's important work on the " Geology of 

 South Australia" (Adelaide, Education Dept., 191 8, p. 543), 

 and J. C. Branner's " Outlines of the Geology of Brazil " to 

 accompany the Geological Map of Brazil (Bull. Geol. Soc. Amer., 

 1 91 9, 30, 189-338), are too comprehensive to comment upon 

 profitably in a short paragraph. 



Petrology of Igneous Rocks. — Dr. N. L. Bowen has replied 

 to recent criticism by Prof. Daly relative to his theory of 

 differentiation by crystallisation (Journ. Geol. 191 9, 27, 393- 

 435). He maintains the relative unimportance of syntaxis 

 as a factor in producing the known diversity of igneous rocks, 

 and denies even the possibility of liquid immiscibility in 

 silicate magmas. He accentuates the importance of the 

 " straining-out " process of residual magma at a late stage in 

 crystallisation — filter-press action — as a factor in differentia- 

 tion ; and prefers this, combined with ordinary sinking and 

 zoning of crystals, to Grout's convection theory, as an ex- 

 planation of the differentiation of the Duluth lopolith (see 

 Science Progress, Oct. 1919, p. 219). 



From the Strathbogie (Aberdeenshire) and Lower Banff- 

 shire district, H. H. Read describes igneous rocks of two petro- 

 genetic cycles, separated by an epoch of great earth movement 

 which caused the foliation of the Dalradian Series (Geol. Mag., 

 1 91 9, pp. 364-71). The magmas have each given rise to a 

 series of differentiates, ranging from anchimonomineralic types 

 to granites, with various norites and gabbros as dominating 



