358 GEOLOGICAL SURVEY OF THE TERRITORIES. 
LEAIA LEIDYI T. R. Jones. 
Cypricardia leidyit Lea, sp. Proceed. Acad. Nat. Se. Philadelphia, 1855, 7, p. 341, pl. 4. 
Height of valve, nearly 3; inch. Bnei 
Length of valve, nearly ice inch. Proportion 7 to 12, or 1; 14——. 
*In the *‘ Proceedings Acad. Nat. Science of Philadelphia,” May, 1855, 
vol. 7, p. 341, Dr. I. Lea has described a smal! fossil found by. Dr. Leidy 
in red sandstone at Tumbling Run Dam, about a mile southeast of Potts- 
ville, in Pennsylvania. The specimen consists of the impression of the 
outside of the two valves. It is figured carefully, of natural size, and 
enlarged, in plate 4 (op. cit.1), and is named Cypricurdia Leidyy by Dr. 
Lea, who thus describes it: 
« Shell oblong, round before and truncate behind, very inequilateral, 
striate ; dorsal and basal margins parallel; umbonal slope shortly eari- 
nate; anterior slope with an elevated line from the back to the basal 
margin; Sstrie about twelve, very regular, and nearly equid.stant (bent 
at an angle of 90° at the umbonal slope). Length, two-twentieths, 
breadth, nearly four-twentieths, of an inch.” ‘The shell is accompa- 
nied on the specimen with some obscure impressed linear marks of a 
dlant. 
The figures are reproduced here (Plate 5, figs. 11, 12). pe sandstone 
is referred to the formation called No. 11 by Prof. H. 
D. Rogers in the State Geological Survey of Penn- 
sylvania, and referred by him to the base of the Car- 
boniferous system, put regarded by some geologists 
as the uppermost part of the Devonian or Old Red 
Sandstone. In this formation of sandstone (which, 
with its associated shales, is 3,000 feet thick), foot- 
tracks of reptiles, rain-prints, wave marks, and trails 
of annelids or molluses are not uncommon at two or (\es 
more horizons. Fig. 24.—Leaia leidyi 
Jones then describes as varieties of the foregoing, cnlarsed. After Lea. 
Leaia williamsoniana, from the uppermost coal-measures of Lancashire, 
England, and L. salteriana, from the lower Carboniferous rocks of Fife- 
shire, Scotland. 
ESTHERIA DAWSONI Packard. 
(Plate XXIV, figs. 4, 4a, 4b.) 
Estheria dawsoni Packard, American Naturalist, xv, June, 1881, p. 496. 
We have received through the kindness of Principal J. W. Dawson, 
LL. D., of Montreal, a valve, in partial preservation, of an Estheria quite 
unlike any existing American form. The following account of its dis- 
covery is from Principal Dawson: 
“It was found at Green’s Creek, on the Ottawa River, in nodules in 
the Post-pliocene clay, holding skeletons of Mallotus villosus and other 
northern fishes, and shells of Leda (Portlandia) arctica, Saxicava rugosa, 
&e.; also leaves of Populus, Potamogeton, &e. The. deposit is of the 
age of the Leda clay of the Saint Lawrence (middle glacial) and belongs 
to a period of submergence where, in the bay or estuary then repre- 
senting the Ottawa River, northern marine animals were embedded in 
deposits into which was also washed the débris of neighboring land, 
and of fresh-water streams. The climate at the time was colder than 
at present, and the area of land less, so that, if this Estheria still lives, 
it is most likely to be found in the vicinity of the Arctic coast.” 
This Estheria is entirely unlike any northern American or European 
