1-liii^cr Lake Rctj^ioii of Central X. )'. — Tnrr. 291 
dences indicatin*:^ rejuvenation; Init these studies have not 
prog^resscd far enousj^li to warrant a discussion of them. In 
fact the present paper, leavinfj: the solution of tlie main prol)- 
lem unsettled, would not have been written had it not seemed 
important to present, for the use 'f other workers in the- field, 
the facts which seem opposed to glacial erosion, and the rea- 
sons for believing that rejuvenation by uplift cannot be ig- 
nored as a possilile explanation of the conditions m the Finger 
Lake region. The statement of m\' conviction that the glacial 
ero'^ion theory cannot be accejKed as proved, seems especially 
important in view of the fact that in my earlier ])aper, over- 
looking some of tlie e.'idence. 1 published the conclusion that 
the Lake Cayuga valley owes its great depth to ice erosion. 
Vntil the facts opposing glacial erosion are explained, or until 
the possibilitv of the rejuvenation theory is eliminated, the 
current theory for the origin of these valleys by glacial erosion, 
recentlv revived, cannot be considered established. 
THE TYPICAL SPECIES AND GENERIC CHARAC- 
TERS OF AVICULIPECTEN, McCOY.* 
By Gkorgk H. Gihty. 
Within the past few months I have had occasion to ex- 
amine into the status of ^McCoy's genus AvicuUpcctcn, and 
as the name was found to have been subjected to a variety of 
usage, it seemd that the record of my inquiry and some of 
the circumstances connected with it might be of more than 
personal interest. 
^IcCoy defined this genus in 1851,7 naming no type but 
givii g an illustrative figure and describing two new species, 
A. planiradiatus and ./. nifhi'ciii. The original diagnosis 
and structural figure ma}- be cpioted as follows : 
Incqe.ivalve. more or less inequilateral, straight, or slightly extended 
obliqiu'iy towards the posterior side ; anterior ear flattened, smaller 
than the posterior, siKirpiy and deeply defined, with a deep notch in the 
right valve between a and the body of the siliell iot the passage of the 
byssiis : posterior ear slightly pointed, extending about as far as the 
• Published by permission of the Director of the U. S. Geological Survey. 
f Ann. Xfag-. Nat. Hist.. 2nd ser., vol. vii, p. 171. 
