108 REGINALD A. DALY 
of dominant, common basalt. The syenite and other alkaline 
types have suggested the problem of origins to Marshall. He finds 
no evidence favoring the sediment-syntectic hypothesis in this 
case. A chief ground for doubting it is the assumed lack of lime- 
stone in the volcanic pile. Marshall admits that globigerina ooze 
veneers the submarine flanks of Tahiti, but implies that neither 
ooze, coralliferous limestone, algal limestone, nor shell limestone 
was interbedded with the basaltic flows during the slow submarine 
growth of the volcano. Again one must ask if such interbedding 
can, under the tropical conditions, possibly be doubted. Again, 
too, the required amount of assimilation of limestone and other 
sediments would be small. 
Queensland.—Richards has published an excellent study of the 
Tertiary volcanic rocks of southeastern Queensland.‘ These are 
divisible into three stratigraphic divisions. The lowest is com- 
posed of common basalts. The middle division includes augite 
andesite, rhyolite, comendite, trachyte, soda-trachyte, phonolitic 
aegirite trachyte, and pantellerite. The upper division is domi- 
nantly basaltic, with flows of olivine basalt, olivine-free basalt, 
andesitic basalt, oligoclase basalt, and andesite. The alkaline 
rocks ‘constitute at the most 5 per cent of the volcanic material.” 
Richards regards all types as mere differentiates of a single original 
magma and follows the all too common plan of calculating its com- 
position from the volumes and compositions of the visible rocks 
only. Inasmuch as no reckoning is made of the other magmatic 
phases that must have remained in the magma chambers below 
the earth’s surface, the estimate is entirely misleading and, for its 
purpose, of no immediate value.’ 
On account of the relatively small amount of limestone in the 
country rocks, Richards finds unsatisfactory the sediment-syntectic 
hypothesis in explanation of the Queensland alkalines. However, 
limestone is not necessarily a partner in a syntectic from which 
trachytes, pantellerites, or comendites are differentiates. The 
writer has indicated the grounds for regarding shales and other 
subsiliceous, hydrous sediments as more influential in the generation 
1H. C. Richards, Proc. Roy. Soc. Queensland, XXVII (1916), 105. 
2 The same principle applies to alkaline provinces in general. 
