DECEMBER 22, 1899.] 
ships some of these second-growth forests 
may yet be seen which have been growing at 
least fifty or sixty years. So that the oft re- 
peated remark as to the number of Iowa trees, 
to the effect that their number has greatly in- 
creased since the country has been settled, is 
strictly true.’’ ; 
CONTRIBUTIONS FROM THE NATIONAL HER- 
BARIUM. 
THE Division of Botany of the United States 
Department of Agriculture has issued another 
of its series of Contributions from the National 
Herbarium which have done so much to raise it 
in the estimation of the scientific men of the 
country. The present bulletin (Vol.V., No. 4) 
is mainly from the pen of J. N. Rose, and deals 
mostly with Mexican plants. In his studies of 
Mexican and Central American plants, the 
author proposes a rearrangement of the genera 
of the difficult group Agaveae, illustrating each 
with one or more wood cuts. Another interest- 
ing division of this paper is that on ‘Some 
Mexican species of Thalictrum.’ 
most attractive paper in the bulletin is that en- 
titled ‘Notes on Useful Plants of Mexico.’ 
This takes up in order the cereals and vegeta- 
bles, fruits, beverage plants, seasoning and 
flavoring plants, medicinal plamts, soap plants, 
tanning and dye plants, fiber plants, brush and 
broom plants, fence and hedge plants, plants, 
yielding wool, and miscellaneous useful plants. 
The principal fence plant appears to be the 
giant cactus bearing the name Cereus pecten- 
aboriginum, which often reaches 15 to 20 metres 
(45 to 60 feet) in height, and sends up a multi- 
tude of long, naked branches. These are cut 
into lengths of 18 to 20 dm. (5 to 6 feet) and 
set in rows where they root and form fences of 
the most impenetrable kind. Several fine pho- 
tographs of this cactus, reproduced in half tone 
give one an excellent idea of its appearance. 
The text and half tone illustrations of fibre 
plants are equally instructive. One is struck 
with the ingenuity displayed by the people in 
utilizing the fibre plants of the country, and at 
the same time with the primitiveness of the 
methods employed. 
CHARLES E. BESSEY. 
THE UNIVERSITY OF NEBRASKA. 
SCIENCE. 
Perhaps the - 
UNITED STATES GEOLOGICAL SURVEY. 
In forwarding Part II. of the 19th annual 
report of the U.S. Geological Survey, which 
we hope to review later, the director, Dr. Chas. 
T. Wolcott writes : 
Of its contents (five papers), the first ‘ Phy- 
siography of the Chattanooga District, in Tenn- 
essee, Georgia and Alabama,’ by C. W. Hayes, 
sets forth the results of a study of a region in 
which several distinct types of land surface are 
characteristically developed under such condi- 
tions that the part taken by the several factors. 
can be fairly well determined; it traces the 
process of drainage development and the origin 
of the present land forms upon rocks of diverse 
erodibility and diverse structure ; and, finally, 
by a concurrent examination of drainage and 
surface, reviews the recent geologic history of 
the region. ; 
The second ‘ Principles and Conditions of the 
Movements of Ground Waters,’ by F. H. King, 
contends that the water which occupies the in- 
terior of the earth’s crust, is, like that of the 
ocean and of the atmosphere, constantly in 
motion. These motions are at once numerous, 
extended and very complex, and are brought 
together and discussed under three categories, 
gravitational, thermal and capillary. 
The third, ‘ Theoretical Investigation of the 
Motion of Ground Waters,’ by C. S. Slichter, 
relates to an investigation of the general prob- 
lem of the flow of water through porous soils of 
rock. 
The fourth is entitled, ‘Geology of the Rich- 
mond Basin, Virgini-’ by N.S. Shaler and J. 
B. Woodworth. The Richmond area is impor- 
tant from the economic as well as the scientific 
point of view. It contains the only freely 
burnable coal lying immediately adjacent to 
tide water in the eastern portion of the United 
States. The quantity and quality of this fuel 
appear sufficient to give it a value in the in- 
dustrial arts. 
The final paper, ‘ The Cretaceous Formation 
of the Black Hills as indicated by the Fossil 
Plants,’ by L. F. Ward, with the collaboration of 
W.P. Jenny, W. M. Fontaine and F. H. Knowl- 
ton, presents a brief historical review of the in- 
vestigations of earlier explorers, followed by 
specific chapters on the Minnekahta, Blackhawk 
