342 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, No. 15 
ward, and that the magma was able to come to the surface because 
of the freedom from pressure brought about by the laying bare 
of the surface of the lower basaltic layer. This is plausible and in- 
genious, but it was shown by Geikie, in his work on the ancient vol- 
canoes of Great Britian, that similar lavas were being poured out in 
the Thulean region as far back as Paleozoic and even pre-Cambrian 
time. We know also that similar enormous floods of plateau basalts 
were being poured out elsewhere, as in India, Siberia, and in the 
northwestern United States, at approximately the same time as those 
of the Thulean region, and that these other outflows can not be 
connected with relief of pressure due to sliding of the upper parts of 
the crust. The Thulean basalts must then be regarded as indecisive. 
Farther south we find, according to Wegener’s maps, Ireland and 
Great Britain abutting against Labrador and Newfoundland, and 
(presumably) France, with the Armorican peninsula, alongside of 
the Maritime Provinces and New England. An outstanding petro- 
graphic feature of Labrador and Newfoundland and eastern Canada 
is the presence of many large areas of pre-Cambrian anorthosite. 
Nothing corresponding to them occurs in western Europe, at least in 
the parts that would correspond with the American occurrences on the 
Wegener hypothesis, although areas of anorthosite occur in western 
Norway, as we have seen, these having no corresponding represen- 
tatives in Greenland. The extensive Triassic ‘‘trap sheets” of New 
England, Nova Scotia, and Labrador also do not have their equiva- 
lents in western Europe, except that many such basaltic rocks of 
various ages occur in Great Britain and Ireland. It is to be noted, 
moreover, that these more northerly occurrences of Triassic traps 
in America are but the end members of a long series of plateau 
extrusions which extends far down through New Jersey and Pennsyl- 
vania into the Southern States. This important petrographic feature 
has no counterpart across the Atlantic. Another marked petro- 
graphic feature of New England and eastern Canada is the occurrence 
of many small areas of decidedly sodic rocks of very early geologic 
age, most of them east of the Appalachians. Somewhat similar highly 
sodi¢ areas are present in northern Scotland and elsewhere in the 
British Isles, but they do not seem to be represented in Labrador and 
Newfoundland opposite them. Those of the Novanglian Region may 
be represented by the somewhat alkalic rocks of central France, but 
these are of much later date and are, furthermore, much less sodie. 
The dominant feature of the Appalachian region, along the Atlantic 
coast of the United States, is the abundance of granite which is quite 
