eoo 
1158 General Notes. [November, 
In this manner the Donbs traverses the basin of Morteau, receiv- 
ing a rivulet from its interior as it passes.——M. Cotteau also 
contributes a note upon the Jurassic echinids of Algeria, forty- 
seven in number. One only of these species is found in the Ox- 
ford stage ; thirty-seven to the upper coralline, and seven seem to 
be Kimmeridgian. Nineteen are new and known only in Algeria, 
while the remainder occur in Europe, usually at the same strati- 
graphic levels. 
Tertiary —The cerebral hemispheres of Arctocyon dueilit and 
Pleuraspidotherium aumonieri, discovered by M. Lemoine in the 
Eocene of the environs of Rheims, are stated by that geologist to 
be so reduced in dimensions as to be scarcely superior in trans- 
verse diameter to the olfactory or the optic lobes, the latter of 
which are entirely uncovered ——M. Hebert (Bull. de la Soc. 
Geol. de la France, 1882) has described in detail the nummulitic 
group of the south of France. This group belongs to the M 
dle and Upper Eocene, and occurs in the Central Pyrenees, at 
Chalosse, at Corbiéres and Montagne Noire, and in the environs 
of Nice. 
General —Mr. G. K. Gilbert states that the great fault along the 
western base of the Wasatch mountains is wanting opposite pe 
Lake City. He suspects that the fault will yet be compl l 
at that point, and that when the slip occurs it will cause an «at 
quake which will destroy Salt Lake City. 
MINERALOGY.! 
EXPERIMENTAL STUDIES upon Rocxs.—M. J. Thoulet, after c 
ploring the absence of general results arrived at by lithologists, 
has proposed to himself the study of all the physical pro thus 
of the same rock in order that, by a comparison of the data : 
obtained, any relations which exist between these diverse prf | 
ties may be discovered, and at all events the physical eor ) 
the rock may be systematically stated. He holds pe. g the 
should be systematized by the common application O! sf rocks 
physical and natural sciences to the study of the geneet mnt 
and shows the necessity of obtaining, in the first place, x4 
cific heat and resilient elasticity or power of rebounding: eyed 
This method of proceeding, although laborious, ' of 
be alone capable of furnishing certain results. n 
1 Edited by Professor H. Carvitt Lewis, Academy of Naina m g = 
delphia, to whom communications, papers for review, ¢tc-» shou gabe 
* Bull. Soc. Mineralogique de France, T. vi, No. 6, p- I61. 
