1881. ] Geology and Palecniology. li 
them show the beaks (umbones), though the form of the remain- 
der of the shell indicates that they were situated nearer the mid- 
dle of the valve than usual, 7 ¢., between the middle and the an- 
terior third of the shell. The shell is deep, probably more so 
than in £. jonesii, though the valves have evidently been flattened 
and somewhat distorted by pressure, but apparently the head-end 
as more truncated than in Z. jonesii, as the edge of the shell and 
the parallel lines (or ridges) of growth along the head-end are be- 
low bent at right angles to the lower edge of the shell. The raised 
lines of growth are very numerous and near together; they are 
of nearly the same distance apart above near the beaks as on the 
lower edge. The very numerous lines. of growth are thrown up 
into high sharp ridges, the edges of which are often rough, finely 
granulated, and often the valleys between are rugose on the sur- 
face. In one or two places a row of papilla for the insertion of 
spinules may be seen where the shell has been well preserved, and 
between many of the lines of growth there are irregular superfi- 
cial ridges. Length 10 mm.; depth 7. : 
The valve is evidently that of an Estheria, much truncated an- 
teriorly, and with the lines of growth much thicker, higher and 
closer together than in any North American species known to us, 
d may prove when better specimens are found, to be allied to 
the tertiary Siberian E. middendorfi. 
The species is named in honor of the discoverer, J. W. Daw- 
son, LL.D., who has so persistently and ably investigated the 
Leda clays of Canada.—A. S. Packard, Fr. 
Miocene Docs.—In the Bulletin of the Hayden Survey, Vol. 
VI, p. 177 (Feb., 1881), I gave a synopsis of the genera and spe- 
cies of this family found in the Lower Miocene formation of the 
Western Territories. These numbered seven and‘nineteen respect- 
> - 
Tt 
3; M.}. Its reference to the Canide is not certain. (2) Itseems 
Icticyon as follows: Oligobunis, 1. 3; C.}; Pm. 4; M.3; an in- 
ternal tubercle of the inferior sectorial, which has a basin-shaped 
; cyon, 1.3; C.4; Pm.$; M.$; no internal tubercle of 
the inferior sectorial, which has a trenchant heel—Z£. D. Cope. 
Retscn’s Microscopic INVESTIGATIONS OF THE STRUCTURE OF 
Coar}—Whilst there is a general agreement among geologists 
that the coal of all geological formations is of vegetable origin, 
Neue Untersuchungen ueber die Microstructur. der Steinkohle des Carbon, der 
