106 REGINALD A. DALY 
apparent or real absence of basic sediments at those places is not 
immediately compelling to anyone who remembers the complex 
conditions due to deep erosion, to inadequate exposures, to “‘stac- 
cato”’ injection,’ to the lateral migration of magmas, as proved in 
the case of sill or laccolith, and to the probable fact that most 
pre-Cambrian granite (and orthogneiss) has been concordantly 
injected and may therefore in a given instance cover thick, basic 
sediments not locally exposed. The last-mentioned principle 
affects the negative evidence for appropriate country rocks around 
the alkaline eruptives of the Julianehaab district, the Kola Penin- 
sula, Cripple Creek, certain localities in New Hampshire and East 
Africa, etc. 
The repeated objection that some granites, granodiorites, and 
other subalkaline bodies cut limestones and yet do not show obvious 
chemical reaction with the sediments is not necessarily valid. Such 
contacts may simply indicate the respective magmatic temperatures 
to have been too low for the reaction. Before stoping or other 
mechanical movements had established any of these contacts the 
temperature may have been higher, so that solution of limestone 
was then possible. However, unless the limestone made a consider- 
able part of the whole rock mass dissolved (otherwise likely to be 
composed of siliceous country rock), the effects of the solution of 
limestone might be masked by the differentiation of each great 
body of magma. In a special case a batholith may have stoped 
its way to the limestone just as the dissolving power of the magma 
was approaching zero. 
Hawait.—Cross’s valuable memoir on the Hawaiian lavas bears 
the conclusion that the alkali-rich rocks and melilitic rocks of the 
archipelago are “‘products of the same general process of differ- 
entiation [of original basalt] as the other rocks with which they are 
associated.” He rejects the sediment-syntectic hypothesis, partly 
because he doubts that limestones are ‘‘associated with the older 
lavas of the archipelago.” He fails also to see how “superficial 
deposits of coral limestone . . . . can gain access to the volcanic 
conduit in mass sufficient to produce any notable result.” Yet 
Cf. R. A. Daly, Amer. Jour. Sci., XLIII (1917), 444. 
2'W. Cross, op. cit., p. 90. 
