REVIEWS AND BOOK NOTICES. 103 
But this centre was non-existent before the Devonian period, and 
the centre for this must have been to the north-east whence the 
great mass of older Appalachian pA E was derived. In the 
Carboniferous period there was also an eastward distribution from 
the Appalachian, and links of connection in the Atlantic bed be- 
tween the floras of Europe and America. In the Devonian such 
connection can have been only far to the northeast. It is there- 
fore in Newfoundland, Labrador and Greenland that we are to look 
for the oldest American flora, and in like manner on the border of 
the old Scandinavian nucleus for that Eri Europe. Again, it must 
have been the wide extension of the sea of the Corniferous lime- 
stone that gave the last blow to the se a flora of me Lower 
Devonian ; “and the re-elevation in the middle of that epoc 
brought in the Appalachian ridges as a new centre, and establiched 
a connection with Europe which introduced the Upper Devonian 
and Carboniferous csr Lastly, from the comparative richness 
of the later Erian flora in Eastern America, especially in the St. 
John beds, it might be: a fair inference that the northeastern end 
of the Appalachian ridge was the original birth-place or centre of 
creation of what we Sed call the later Paleozoic flora, or of a 
large part of that flora 
Finally, in a supplementary section Dr. Dawson gives us his 
theoretical views as to the origin and extinction of species. 
‘t Some of the forms reckoned as specific in the Devonian and Car- 
boniferous may be really derivative races.” These may have 
originated in one or more of the following ways ;— (1) By a nat- 
ural tendency in synthetic types to become specialized in the di- 
rection of one or other of their constituted elements. (2) “By 
embryonic retardation or acceleration in the manner illustrated by 
Hyatt and Cope.” (3) ‘The contracting and breaking up of flo- 
ras.” (4) ‘*The elevation of a great expanse of new land at the 
close of the Middle Erian and the beginning of the Coal period, 
would.by permitting the extension of species over wide areas and 
fertile soils, and by removing the pressure previously existing, be 
eminently favorable to the production of new, and especially 
of improved varieties.’ 
ÅNTHROPOLOGICAL InstiruTE oF New York.*—In a former 
number we called attention to the organization of this society, of 
which we have now received the first fruitsin the form of a ve 
interesting and important number of its Journal. The publications 
* Journal of the Anthropological Institute of New York. Vol. i, No.1. 8vo pamph. 
Pp. 100. New York. 1871-72. [50 cts. 
