APRIL 12, 1901.] 
SHORTER ARTICLES. 
A NEW OCCURRENCE OF CASSITERITE IN 
ALASKA.* 
DuRING the past season while making a hasty 
reconnaissance of the York gold field of Alaska, 
my attention was called to some auriferous 
gravels which carry a large percentage of 
stream tin. This stream tin is found in consid- 
erable quantities on Buhner Creek, which enters 
the Anakovik River from the west about three 
miles from Behring Sea. The occurrence is 
perhaps best located by stating that it lies some 
ten miles east of Cape Prince of Wales and 
hence very near the northwestern extremity of 
the continent. On Buhner Creek some two to 
three feet of gravel overlie the bed rock which 
consists of arenaceous schists which are often 
graphitic, together with some graphitic slates. 
The bed rock is much jointed, the schists being 
broken up into pencil-shaped fragments. They 
strike nearly at right angles to the course of the 
stream and offer natural riffles for the concen- 
tration of heavier material. A hasty reconnais- 
sance of the drainage basin of this stream, 
which includes not more than a square mile of 
area, showed the same series of rocks through. 
out its extent. At a few localities some deeply 
weathered dark green intrusives were found, 
which, on examination by the microscope, were 
found to consist almost entirely of secondary 
minerals. In some cases, however, a little 
plagioclase was still unaltered and a suggestion 
of ophitic structure remained, so that these 
are probably of a diabase character. The slates 
and schists are everywhere penetrated by small 
veins consisting usually of quartz with some cal- 
cite and frequently carrying pyrite and some- 
times gold. These veins are very irregular, 
often widening out to form blebs and again con- 
tracting so as not to be easily traceable. 
The stream tin is concentrated on the bed 
rock with other heavy minerals and was found 
by the miners in the sluice boxes. A sample of 
the concentrate in one of the sluice boxes was 
examined by Mr. Arthur J. Collier and yielded 
the following minerals: cassiterite, magnetite, 
ilmenite, limonite, pyrite, fluorite, garnets and 
* Published by permission of the Director of the U. 
S. Geological Survey. 
SCLENCE.. 
593 
gold. The determination of percentage by 
weight was as follows: ninety-five per cent. 
tin-stone, five per cent. magnetite ; other miner- 
als five per cent. The cassiterite occurs in 
grains and pebbles, from those microscopic in size 
to those half an inch in diameter ; they have 
sub-rounded and rounded forms. In some 
cases there is a suggestion of pyramidal and 
prismatic crystal forms. The cassiterite varies 
from a light brown color to a lustrous black. 
A second locality of this mineral was found 
on the Anakovik River half a mile below the 
mouth of Buhner Creek. Here the cassiterite 
is also found with the concentrates from the 
sluice boxes of miners. I observed one speci- 
men from this locality which was some two 
inches in diameter. 
During the hasty reconnaissance no acid in- 
trusives nor pegmatite veins were found in the 
drainage basin. The nearest known ‘granitic 
rocks are in the biotite granite mass which 
forms the promontory of the Cape Prince of 
Wales. It is hoped during the coming season 
that more detailed work in this region will 
throw further light on these interesting de- 
posits. 
_ALFRED H BROOKS. 
NOTES ON PARASITES —56: ECHINOSTOMUM 
BURSICOLA LOOSS AND E. CLOACINUM 
BRAUN, FROM A NOMENCLA- 
TURAL STANDPOINT. 
Proressorn Max BRAUN * has recently pro- 
posed the name Echinostomum cloacinum as a 
substitute for Distomum bursicola Creplin, upon 
placing this species in the genus Echinostoma. 
Braun’s reason for changing the specific name 
is that there is already an Echinostomum burst- 
cola Looss, 1899, and he assumes that this in- 
validates the specific name bursicola Creplin, 
1837. 
In this decision, Braun has fallen into error. 
It is not bursicola 1899 which invalidates burst- 
cola 1837, but the latter invalidates the former. 
Hence £. cloacinum Braun, 1901, must fall as a 
*1901.—Ueber einige Trematoden der Crep- 
lins’chen Helminthensammlung. Cent. f. Bakt. 
Paras. u. Infek., XXIX., 1 Abt., No. 6, Feb. 25, 258- 
260. 
