476 
Professor Agassiz has caused to be prepared for sale or exchange 
at the Museum of Neuchatel a series of casts of the internal cavi- 
ties of 101 recent bivalve and 101 recent univalve shells, for the 
purpose of illustrating fossil genera and species, the shells of which 
have in many cases entirely perished. He has also caused to be 
prepared for sale at the same establishment casts of 500 species of 
fossil Echinoderms—all these casts have recently been added to the 
collection of shells in the British Museum. 
PHOTOGRAPHY. 
A valuable application has been made by Captain Ibbetson of | 
a Photogenic process for rapidly producing perfeet drawings of 
fossil shells on metallic plates, from which, when fixt by. the en- 
graver’s tool, lithographic transfers may be rapidly multiplied to an 
almost indefinite extent. This process promises to be applicable to 
organic remains of every kind, and consequently of great utility. 
in Paleontology. From a beautiful fossil starfish I sent by one day’s 
mail to Captain Ibbetson, in London, I received, by the next mail, 
a parcel of most exact impressions, taken from a photographic 
drawing, transferred to stone by the process above mentioned. 
PHYSICAL GEOLOGY. 
It is not long since, in the Transactions of the Cambridge Phi- 
losophical Society (Vol. 1V., 1838), we rejoiced, to see a mathe- 
matician of such high authority as. Mr. Hopkins, in a paper. en- 
titled “ Researches in Physical Geology,” adopting this term as one 
of acknowledged and deserved aeceptance in our nomenclature, and 
to find him asserting, “ that we are now arrived at that stage of 
geological science, in’ which we are able to reeognize certain well- 
defined geological phenomena distinctly approximating to geometri- 
cal laws,” and following up this assertion by the first example of a geo- 
logical investigation conducted on principles supplied by mathematical 
analysis. The apparent irregularities which the disturbances of the 
globe seem at first sight to present, being thus reduced under the do- 
minion of mathematical calculation, we hail in this paper the com- 
mencement of a series of physical deductions, explanatory of the law 
of parallelism, which is so constantly observed in the case of mineral 
veins, faults, and anticlinal lines; and referring this law to a mecha- 
nical cause, demonstrable by the test of exact geometrical proof. 
We have recently witnessed another investigation of this -high 
order, respecting the necessary relations between observed) pheeno- 
mena and the physical cause to which they owe their origin, in a 
communication to our Society by Mr. Hopkins “ On the parallel lines 
of simultaneous elevation in the Weald of Kent and Sussex*.” In 
M. Tesson, of fossil shells of the genus Conus, in the Lias or Inferior Oolite 
of Normandy, near Caen. Fossils of this family have long been known to 
abound in the Tertiary strata, and supposed not to occur in any lower 
formation. 
* A district long ago and ably illustrated by the researches of Mr. 
Mantell 
