SCIENTIFIC SUMMARY. 
95 
continues to do so in proportion as the crystallisation proceeds. Hence the 
density of the crystals forming is less than that of the solution from which 
they form. Surprising as is this deportment of a gradually crystallising 
solution of Glauber’s salt, that of a so-called supersaturated solution is still 
more surprising and remarkable. If such a one by careful treatment is 
cooled down to 0°, and then made to crystallise suddenly, the crystal cake 
formed, which constitutes a compact solid mass, exhibits an extraordinary 
increase in volume, and on further cooling to about 10° C. below zero, con- 
tracts more and more. As in this condition of the original solution there 
can be no question of a separation of crystals as in the former case, it seems 
(like water below 4°) not to follow the law according to which bodies con- 
tract by diminution of temperature. 
GEOLOGY AND PALAEONTOLOGY. 
The Entire Skeleton of a Mastodon has just been discovered in a peat-bed 
near Troy. The jaw-bone was found near the surface. At a depth of about 
50 feet the remaining bones were found. The tusks were very nearly 6 feet 
long and about 9 inches in diameter. One of them, upon exposure to the 
light, crumbled to pieces like clay, resembling that substance in appearance 
and texture. The ribs, of which there were 14 found, are about 4 feet long, 
the largest being 4 feet 9 inches. The upper jaw-bone is 4 feet 9 inches 
long from the extremity of the mouth to the cranium, and across the fore- 
head measures about 8 feet. So heavy is it that it was with difficulty four 
labourers could move the mass. The sockets in which originally were 
located the eyes of the monster are almost large enough to admit the head 
of a man. The hip-bone is 5 feet long, and weighs 100 pounds ; the 
shoulder-blades measure 2 feet 9 inches, and weigh about 50 pounds each. 
The bone of the leg at the knee-joint measures 13 inches in diameter. The 
vertebrae of the back-bone are 8 inches in diameter. The other fragments 
found are in harmonious proportion to those already mentioned. 
On the Distribution of Life Docks. — Mr. H. G. Seeley read a paper at the 
late meeting of the Cambridge Philosophic Society upon “ The Laws Regu- 
lating the Distribution of Life of Rocks.” Mr. Seeley stated that in all denu- 
dation, whether marine or subaerial and fluviatile, the crystalline rocks which 
underwent this process were again deposited in the following order : (1) 
sand, (2) clay, (3) limestone j the second overlapping and appearing at the 
junction, to be superposed to the first, and the third to the second. Hence 
these deposits, which at first sight appeared to be successive, might in 
reality be contemporaneous. Again, deposits were commonly assumed to be 
contemporaneous when they contained the same fossils ; but upheaval and 
depression would cause the fauna of any locality to move ; so that remains 
of the same species might be deposited necessarily in different deposits. He 
also considered species to be re-transmutable, and to be affected by the 
physical conditions under which the animal was living. Therefore he main- 
tained that strata could not be identified by these means, but by discovering 
the physical conditions under which they were deposited, and by other 
