PROCEEDINGS OF SCIENTIFIC SOCIETIES. 62 1 
hardness and heaviness of the brown hematite, and for the thickness 
of its beds. The ore lumps would be mixed not only with the rubbish 
of neighboring rock-beds, but with the remains of plants that grew 
during the accumulation of the ore-lumps, such as the Brandon and 
Mont Alto lignites. Lumps of carbonate of iron, found in some such 
deposits, go towards showing that the ore was originally a oo 
and afterwards altered as the coal-measure carbonates so often a 
The author thought these lumps were not concretions. 
“ The Winooski Marble of Colchester, Vermont.” By C. H. Hitch- 
cock. and polished specimens of a beautiful marble, obtained 
miles from Burlington, were exhibited. 
from pastas less than six 
and is a silicious 
It belongs to the lower part of the Potsdam group, a 
dolomite. It contains eee of calcite enclosing ners silica, 
which render the ston to saw than statuary marble. 
The prevailing color is some eerie of red, with variations of white 
brown, chocolate, and yellowish tint 
“ The Distortion and sbi of Pebbles in Conglomerate.” 
cheo dv 
h 
mical character had been altered by metamorphism, so that frag- 
ments, originally an impure limestone or a schist, had become changed 
into quartz. The process had probably been carried so far in some 
instances specified, that the original sandstone and conglomerates had 
been converted into schists, gneiss, and’ granite. The agents pro- 
ducing these changes were thought to be the chemical action of infil- 
loosely cemented coarse gravel, with round pebbles; but where folds 
abounded, the stones had been indented, flattened, and bent, and the 
See were noticed eis Middle- 
j llingham, Mass., Washington County, Mount Battie, an 
Sardy River ` Plantation, Me., san Wallingford, and Plymouth, Vt., 
elflue in Switzerland, and the Permian conglomerate in Eag- 
land, etc. The opinions of eminent European geologists in favor of 
a superinduced distortion were quoted, as well as the experiments of 
Mr. Sorby, illustrating the greater efficiency of chemical action under 
press 
