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POPULAR SCIENCE REVIEW. 
during which the atmospheric agencies have been modelling the minor features 
is inconceivably great. The recent temporary depression beneath the waters of 
the glacial sea did little or nothing in the way of denudation, the principal 
effect then being the transport of blocks, or the washing about of materials 
already loose on the surface. — Vide Geological Magazine , May. 
The Difference between Coal and Cannel is in all cases better marked than 
some geologists imagine — at least, if we are to believe the statements made in 
a recent communication by Mr. J. Rofe, F.G.S. Though both are undoubt- 
edly of vegetable origin, they are clearly distinguishable by the fossils they 
contain. In the body of coal the fossils are nearly all, if not entirely, 
vegetable, whilst in the cannel, fish-remains are frequently present. Another 
remarkable difference is shown in the distillation of the two substances. In 
preparing gas from cannel it is necessary to have the pipes from the retorts much 
larger than when coal is employed, since they are liable to become choked by 
a deposit which was formerly thought to be pitch, but which is really found 
to consist of crystals of chloride of ammonium bound together by tar. Con- 
cerning the origin of this, Mr. Rofe asks, — “ May not this large quantity of 
chloride of ammonium be accounted for by the cannel bed having been de- 
posited in saltwater, the habitat of the fish found in the cannel, the seawater 
furnishing the chlorine for this salt ? I am fully aware that the distillation of 
common coal gives salts of ammonium ; but they are principally carbonate, 
sulphate, and sulphide, with very little chloride, and these are all found in 
what is technically called the ammoniacal liquor. The cannel also gives these 
salts in solution in the liquor in addition to the crystals sublimed into the 
pipes as above stated.” 
Erosion of the Surface of the Country around New York. — An instructive 
and useful series of diagrams illustrating the above were recently exhibited 
by Professor Stevens at the American Institute. The Professor considers 
that it is an evident truth that the irregularities in the surface of the State 
were caused by disintegration and denudation, the consequence of climatic in- 
fluences. The first diagrams — all taken from actual surveys — showed a section 
of the State east and west, presenting a succession of plateaux rising at some- 
what regular distances and heights, one above another ; the second plateaux 
appearing on the horizon when standing on the first, the third when standing 
on the second, and so on. The section north and south presented a strik- 
ingly different appearance, viz. a succession of hills and valleys, stretching 
from one border of the State to the other, and terminating with the broad, 
elevated coal-fields of Pennsylvania. The ridges of some of these hills are so 
narrow that two horsemen can with difficulty ride side by side. All the 
summits of the ridges are somewhat on a level, and all below the level of 
Pennsylvania coal. His diagrams went to show that the coal-fields had in 
times long past covered the southern part of the State of Hew York as they 
now cover Pennsylvania, but had subsequently been washed away. 
The Fossil Remains of Stylodon pusillus. — Specimens of the lower jaw and 
teeth of this oolitic mammal having been forwarded to Professor Owen 
by the Rev. P. B. Brodie, the former has given a minute account of the 
fossil in the Geological Magazine for May. The part of the lower jaw is 
imbedded in a small block of the matrix, with the outer surface exposed : it 
includes the proportion of the ascending ramus supporting the coronoid pro- 
