FEBRUARY 1, 1901.] 
against it. The three mountain masses have, 
however, as shown by studies of the past sea- 
son, been centers of local glaciation. In the 
Kiglow-aik range the valleys are glaciated to 
an elevation of 500 feet above the valley floor, 
and the moraines marking the limits of this 
glaciation were deposited close to tide-water. 
The evidence of ice action consists of cirques, 
U-shaped valleys, morainic topography, and 
glacial erratics. Indeed, in some of the higher 
valleys still exist the shrunken remnants of the 
former valley glaciers. These small glaciers, 
in latitude 65, are, as far as known, the most 
northerly on the continent. 
The high benches and terraces show that the 
western part of the peninsula has been elevated 
600 or 800 feet in recent times. This elevation, 
however, antedates the maximum extension of 
the valley glaciers above described. 
A.C. SPENCER: The Physiography of the Copper 
River Basin, Alaska. 
The observations made by Messrs. A. C. 
Spencer and F. C. Schrader during the summer 
of 1900, establish the existence of a peneplain in 
the Chugatch Mountains, between the coast 
and the interior basin of the Copper and Chitina 
(Chittyna) rivers, and in the adjacent moun- 
tains at the heads of the Chitina, White and 
Tanana rivers. 
The peneplain is now a dissected plateau 
with an elevation of more than 6,000 feet. 
Above it rise Mt. Blackburn and Mt. Natzahat 
to elevations of several thousand feet, the for- 
mer, at least, being of extrusive origin. ~The 
age of this marked physiographic feature is not 
earlier than late Cretaceous nor later than Mio- 
eene. As the Eocene and Miocene are known 
to have been periods of baseleveling in western 
North America, it is probable that the peneplain 
is of Tertiary age. Whether it should be corre- 
lated with the Yukon plateau, considered as 
Miocene, or whether it is an older feature, has 
not been determined. It is*of the same order 
of maturity as that plateau, and if it can be 
shown to be of the same age, its present altitude, 
several thousand feet above the adjacent por- 
tion of the great interior plateau of Alaska, 
shows that there has been faulting along the 
scarp which the St. Elias Range and its north- 
SCIENCE. 
189 
western extension present towards the north- 
east. 
F. L. RANSOME, 
DaAvib WHITE, 
Secretaries. 
BIOLOGICAL SOCIETY OF WASHINGTON. 
The 332nd meeting was held on Saturday 
evening, January 12th. 
W. H. Dall exhibited a skiagraph of a num- 
ber of univalve mollusks, taken by a compara- 
tively short exposure to the X-rays, and yet in 
spite of their calcareous nature showing the 
structure and form of the interior whorls very 
distinctly. 
Vernon Bailey showed a specimen of a com- 
mercial skin of a grebe, saying that the grebes, 
as well as other water fowl, were being killed 
in great numbers in the shallow lakes of Oregon 
and Washington, particularly in the Klamath 
lakes, and that it was to be hoped that some- 
thing might be done to protect these birds before 
it was too late. 
William Palmer exhibited a series of speci- 
mens of the Cuban branching fern, Gleichenia 
dichotoma, describing its various stages of growth 
and comparing them with those of other species. 
Frank K. Cameron spoke of ‘The Formation 
of Black Alkali by Plants,’ stating that it has long 
been believed that certain plant varieties culti- 
vated on the arid soils of the West can cause an 
accumulation of sodium carbonate or ‘black 
alkali.’ This question has received some at- 
tention in the past, notably by Hilgard in Cali- 
fornia and Goss in New Mexico. An examina- 
tion of the question in the laboratory of the 
Division of Soils, U. S. Department of Agricul- 
ture, indicates that in some cases there is an 
enormous accumulation of sodium in the leaves 
and stems of certain plants, more than sufficient 
to combine with the inorganic acids present and 
therefore in organic combination. On decay 
this material yields considerable amounts of 
alkali carbonates, which accumulate on account 
of the peculiar conditions of moisture and 
drainage which obtain for soils in arid regions. 
The study has led incidentally to a discussion 
of the phenomena involved in the absorption 
of mineral salts by plants, from the point of 
view of the chemist; and lines of investigation 
