aE NTR tee seamen ETS 
L. Agassiz on the Ichthyological Fauna of Western America. 71 
posed that the rise and fall which takes place during periods of 
from three to seven years, to be possibly the effect of increased 
depth of water in the Lake, caused by an unusual amount of snow 
on its borders and tributary streams, or an uucommon rainy sea-, 
son; and that it even appeared from an extract from the New 
York Advertiser, that a gentleman just then (1828) returned from 
atour to the West, had informed the editor that the waters of 
Lakes Ontario and Erie were then nearly a foot higher, while 
those of Lake Superior were considerably lower than ever known. 
The General was therefore led to suggest that, to obtain full, and 
exact data as to the rise and fall of the different Lakes tde- 
guages should be placed at a number of points an the shore of 
each, both in their narrowest and broadest dimensions, and the 
changes carefully observed for a whole year, or at least for several 
months, and accurate tables kept of the times and extent of each 
flux and reflux, in which the position, as respects the meridian 
and the phases of the moon, and also the course of the winds 
should be noted ;—a plan which, it will be perceived, is very 
similar to that proposed by myself in my late paper on the estab- 
lishment of simultaneous meteorological observations. 
(To be continued.) 
Arr. XII—Synopsis of the Ichthyological Fauna of the Pacific 
_ Slope of North America, chiefly from the collections made by the 
U. 8. Expl. Exped. under the command of Capt. C. Wilkes, 
with recent Additions and Comparisons with Hustern types ; 
by L. Acassiz. 
. CypRINorDs. 
Would leave the impression that nothing like them is to be found 
in any other part of the world. 
