Geology and Natural History. 489 
In this table the column « gives the cubic coefficient of extension 
referred to the millimeter as the unit of length; column @ gives 
the cubic coefficient of expansion for 1°C.; column 6 gives the 
It will be seen that it forms a very small fraction of the 1 
lt is thus easy to understand why it has not yet been possible to 
raise the temperature of a solid by compression e als 
: : me 
that the latent heat of expansion exerts a very small influence on 
IL GroLtocy AND NATURAL History. 
Wyoming Coal Formations.—Prof. E. D. Core describes, in 
hil. Soe. 
Philad., a 1 : 
by Mr. Meek and Dr. Bannister, at Black Butte Station, on the 
Union Pacific Railroad, in Wyoming Territory. In this, as well 
as in a later paper published in the American Naturalist on the 
age of the Wyoming coals, Prof. Cope remarks, that the determi- 
nation of the affinities of this Saurian proves that these coals, 
which hold a lower position, belong to the Cretaceous age, and 
not to the Tertiary, and he writes as if all others had been in error 
on the age of the deposits. Prof. Cope was doubtless not aware 
that Mr. Meek had, in 1871, referred Dr. Hayden’s collections from 
this formation on Bitter Creek, at Point of Rocks, to the Cretace- 
ous ;* and that this same careful paleontologist had also referred 
the coal-bearing rocks of the same great series at Coalville, Utah, 
and at Bear River City (Sulphur Creek), Wyoming, to the Creta- 
ceous in 1870, as did also Mr. King and Mr. Emmons.+ ; 
as long back as 1860, Mr. Meek, in connection with Mr, Engel- 
t. Simpson’s collections from these rocks, in- 
a 
the locality and stratigraphical position of the Hallville coal mi 
be had then never visited, and suppos 
ward, and at a much 
Jardin Fruitier du Muséum, un Ieconographie de touts les Espéces 
et Varietes d’Arbres Fruitiers cultives dans cet Etablissement, &c. 
* Hayden's Report of 1871, p. 375. + King’s 4to Report of 1870, p. 461. 
¢ Proc. Ac. N. Sci., Philad., 1860, p. 130. || This Journal, March, 1871, i, 195, 
Am. Jour. a ae Serres, Vou. IV, No. 24.—Dec., 1872. 
