Foreign Literature and Science. 381 
account of Travels through part of the United States and 
Canada, in 1818 and 1819, intended chiefly to illustrate 
subjects connected with the Moral, Literary, and Religious 
condition of the country. 
Those who enjoyed the pleasure of Mr. Duncan’s 
acquaintance, while travelling in this country, will expect 
much from his intelligence and candor, and we confidently 
believe they will not be disappointed.—Ed. 
3. Fossil Vegetables—We have received from Mr. Adol- 
hus Brongniart of Paris,a work “Sur la classification et la 
distribution des Végétaux Fossiles’’—illustrated by litho- 
graphic plates. It is an elaborate and valuable work and an 
analytical notice of it by Dr. J. G. Percival will appear in 
our next number.—Edhtor. 
Communicated by Dr. Jeremiah Van Rensselaer. 
4. Fresh water formations.—From the new edition of 
Cuvier’s work on Organic Remains, it appears that the fresh 
water formations of Paris and Rome are precisely similar : 
presenting the following order of succession from below up- 
wards. 
1. A compact limestone analogous to the Jura limestone, 
or even perhaps to chalk—rarely containing petrifactions. 
he coarse sandstone formation, composed at its low- 
est part of bluish argillaceous marl, with shells, and towards 
its upper part of reddish sandy limestone, and sometimes 
of marine sandstone. ek 
3. The volcanic breccia, in all its modifications, lying” 
above this formation. $55 : 
e fresh water formation. 
Messrs. Brongniart and Brocchi, who have examined to- 
gether these formations, conclude that there are two kinds 
© fresh water formations, very distinguishable by external 
characters, which indicate their difference of origin. The 
one produced by solution and precipitation, more or less 
pure and crystalline, has issued from the interior of the 
earth with the waters which have carried them to the sur- 
face of the soil. They may be formed at all elevations 
where similar waters may have issued, and the height at 
