SEPT. 19, 1923 WASHINGTON: COMAGMATIC REGIONS 341 
granite, with some distinctly sodic syenite and some gabbro, and there 
are several important areas of anorthosite and related rocks as at 
Bergen. On the east coast of Greenland, as far north as Scoresby 
Sound, besides the pre-Cambrian gneisses and granites, the rocks are 
mostly plateau flows of basalt of Tertiary age, which overlie the gneiss, 
but the extensive Paleozoic granites and syenites, and especially the 
characteristic anorthosites such as are found in Norway, are very rare 
or are lacking entirely. Some small areas of rather alkalic rock 
occur also along the east coast of Greenland, for which there seems 
to be no corresponding areas in Western Norway, unless possibly the 
Christiania region around the corner may be so reckoned. Of the 
plutonic basement of Iceland little or nothing seems to be known. 
It thus appears that Western Norway and Hastern Greenland do 
not show signs of correspondence. 
On the west coast of Greenland the igneous rocks seem to be mostly 
dioritic, with here also extensive flows of basalt and several note- 
worthy areas of highly sodic and very peculiar rocks. Somewhat 
similar dioritic rocks occur on Ellesmere Land, which is virtually a 
northwesterly continuation of the west coast of Greenland. But in 
Baffin Land, which is separated from Greenland by the wide and 
rather deep Baffin Bay and Davis Strait, similar rocks do not appear 
to occur, although little is known of the petrography of this region. 
A large series of rocks mostly from the western and southern parts of 
Baffin Land, brought back by the McMillan Expedition and entrusted 
to me for study, are mostly granitic and gneissoid, and evidently 
belong to the Canadian Shield. No areas of alkalic rocks, correspond- 
ing to those of Julianehaab, Ivigtut, etc., and no extensive basalt flows 
are known from eastern Baffin Land. The evidence therefore, although 
it is imperfect, is adverse to the idea that Baffin Land was once contig- 
uous with the west coast of Greenland, as has been suggested by 
Taylor and by Wegener. 
In discussing this northern end of the Atlantic split it should be 
said that the very extensive area of the Tertiary plateau basalts, 
which are remnants of a land that then covered all the region from 
eastern (and possibly western) Greenland to the Faroes and Franz 
Josef Land, which has been called the Thulean region, is evidence that 
underlying this is a supply of magma of very uniform basaltic compo- 
sition. The outpouring of these basalt flows is later than the Weg- 
enerian fracture and it might be plausibly argued by a follower of 
Wegener that they originated in and thus represent the viscous 
basaltic substratum on which the raft of crystalline crust floated west- 
