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whereas those which formed the border of the crater were of a deep brown 
colour, nearly black. This difference of colour is supposed to be due to the 
influence of the hydrochloric acid, which produced chlorides of iron and 
aluminium, the red colour of the parts when the temperature had been most 
elevated being probably due to the decomposition of the chloride of iron and 
the formation of a peroxide. M. Pissis has also described the character of the 
strata which flank the mountain, but we have not space for a summary of this 
part of his correspondence. 
The Ancient Rhone Glacier. — At the meeting (held at Geneva, in August) 
of the Helvetic Society of Natural Sciences, M. Alphonse Favre read a most 
important paper on this interesting ice-sea. The determination of the alti- 
tudes at which erratic blocks are found along the old line of that immense 
sea of ice, which even in its present diminished size is so striking, and in the 
results of its working upon the general scenery of the country it once covered 
is so picturesque, has occupied much of M. Favre’s time. He believes that 
the determination of these altitudes fixes approximately the limiting level of 
the glaciers in the neighbourhood in which they are found, taking, of course, 
the highest erratics in each district. On this principle he finds that the slope 
of the ice between the Col de Ferret and St. Maurice has been exceedingly 
steep ; thence to Villeneuve, at the head of the Lake of Geneva, much less 
steep ; while from Villeneuve down to the point at which the ice-stream biu?st 
the bounds set by the Jura, where now the Fort de I’Ecluse keeps a jealous 
watch, the glacier has presented a vast horizontal surface. Of course, on the 
Jura itself the descending stream has surged— so to speak — to various heights ; 
but on the left bank, by Medlerie, and the foot of the Dent d’Oche (where, 
however, the ice seems to have risen in a wave), and down to the Voiron, one 
uniform superior limit of altitude is given by the erratics, being about 1,000 
metres above the present surface of the sea, and therefore some 2,000 feet 
above the Lake of Geneva as it now stands. Before finally reaching the plain 
of France, the glacier met with a fresh opposition from the M. Sion, 600 
metres in height, and here again the erratics tell of a horizontal surface. 
Beyond the M. Sion another monticule, the Grolee (533 m.), produced a 
similar result, and then the ice was lost in the plain. 
Solid Petroleum has, according to a statement in a recent Philadelphia paper, 
been found in West Virginia. Some persons oAvniug ground in the district, 
found upon it a hard black substance, which was supposed to be coal. How- 
ever, upon chemical analysis it was found to be solidified petroleum, crystal- 
lized upon the outside of the vein, and granulated within. It lay in a 
stratified form, and the vein was of very considerable thickness. So far as 
traced, the “ lode ” was about a mile in length. The discoverers, who were 
determined to put their acquisition to the test, have found that it yields by 
distniation a pure oil at the rate of from 160 to 170 gallons per ton. The 
mine is situated ten miles from Cairo, and is about thirty miles east of 
Parkersburg. 
