1897.] Recent Literature. 43 
Mr. Oscar Roun has at considerable expense collected together 
series of 86 specimens of rocks from the Keeweenawan, the Penokee and 
the Marquette districts in the Lake Superior region. The collections 
represent all the important rock types found in these districts. They 
are intended more particularly to illustrate the reports of the United 
States geologists upon the copper and iron-bearing series of the Lake 
Superior region, though they may serve also as supplements to the col- 
lections of Paleozoic rocks at present furnished by dealers in geological 
materials, since they embrace specimens from the Algonkean and the 
Archean systems as recognized by the U. S. Geological Survey. The 
collections, having been made at the suggestion of Prof. C. R. Van 
Hise, may safely be accepted as typical. In spite of the great expense 
that has attended the making of the collection its price has been placed 
at $40.00. A rare opportunity is offered to practical geologists and to 
teachers of geology in our colleges to secure a trustworthy set of rock 
specimens from one of the most interesting geological regions in the 
United States. Itis hoped that the offer will be availed of, and that Mr. 
Rohn may be induced to collect from other much discussed districts. 
RECENT LITERATURE. 
Zur palaozoischen Flora der Arktischen Zone by A. G. 
Nathorst, Zur Fossilen Flora des Polarlinder, I, Theil, 1 Lief, 80 pp., 
XVI pl., Stockholm, 1894. 
In this memoir on the Paleozoic Flora of the Arctic Zone, Dr. Na- 
thorst presents a comprehensive and exhaustive review and revision of 
the Paleozoic plant material brought by the various expeditions from 
the Arctic regions. Following in the footsteps of Heer, he has been so 
fortunate as to have in hand not only all the Arctic specimens hitherto 
described, with the exception of the fragments brought by McClintock 
from Mellville Island, but also important later collections made from 
several localities in the Devonian and Eocarboniferous of Spitzbergen 
by De Geer and himself in 1882. 
The results of Nathorst’s work diverge along three lines, viz., the 
material imperfectly or often erroneously figured or described by Heer 
is presented in its true relations with detailed accuracy, and is supple- 
mented by the more recent collections ; the geological age of the fossili- 
