387 
ture (hitherto assumed to be entirely symmetrical) and other sub- 
jects bearing on vegetable anatomy, and the difficulties which 
brought discredit on phyllotaxy all vanish. Perhaps it may fur- 
nish a solution of the problem why wooden poles split in anti- 
dromic spirals, for which phenomenon some people have sug- 
gested the stress of wind on the living tree. 
My work has been necessarily hurried; and I shall be glad 
if others will verify or amend it, and help to fill the many lacunae 
which I am compelled to leave unsupplied. ~ 
PRINCETON COLLEGE, Sept. 7, 1895. 
Description of a new problematical Plant from the Lower Creta- 
ceous of Arkansas. 
By F. H. KNow ton. 
PALEOHILLIA ARKANSANA gen. et. sp. nov. 
Stems hollow, . 5-.75 cm. in diameter, several centimetres long, 
roken; wall two or three layers of cells thick; cells of epider- 
mis of two kinds: 3-5 longitudinal rows of elongated, thin-walled 
Cells that are two or three times longer than wide, alternating with 
broad bands of shorter and more irregular cells; stomata numer- 
©us, confined to the broad bands of irregular cells, arranged in 
three rows, two next to the rows of elongated cells with a row of 
distant ones between; stomata with apparently 4-6, usually 5, 
guardian cells. 
The material upon which this description is based was collected 
by Prof. R. T, Hill, of the United States Geological Survey, dur- 
Ing the season of 1888, while engaged under the auspices of the 
Arkansas Geological Survey in making a general investigation of 
the geology of southwestern Arkansas. It came from a gulch on 
One of the smaller branches of the Muddy Fork of Little River, 
about six miles northeast of Center Point, Howard county. The 
deposits containing these fossils were referred by Prof. Hill to the 
Trinity Division of the Lower Cretaceous. The beds are described 
aS consisting of basal ferruginous sands, succeeded by firm white 
°r yellow sand often filled with small concretions of iron pyrites, 
and mixed with clay. This clay is in sufficient quantity to bind 
the sandy material together “so that in drying it often becomes 
