Ses a eeelindiy, PME OND n> SER aie Spe eT we 
alee 
Scientific Intelligence. 389 
= this Journal. )—I have recently bored a well at Chicago 711 feet in 
epth. The surface rock is the Upper Silurian ; for the first forty feet it 
signs of vil Next he: for 200 feet, — are bands of ed limestone 
At a t depth 2 711 em we penetrated a stream of water which stopped 
further progress. This water is perfectly limpid, and is free from all 
traces of sulphur or other disagreeable minerals, and flows 500,000 gal- 
lons of water per day through a 34 inch orifice. Its head is 120 feet 
above Lake Michigan. 
n the Drift in Brazil, and on decomposed rocks under the Drift 
foun recent observations by Prof. Acassiz. Communicated for this Jour- 
al by Atexanper Acassiz.—At Tijuca, a — of hills about 1,800 
eek high, and about seven or eight miles from Rio, there is a drift hill 
with innumerable erratic boulders as eis as any ever seen in 
New England. Prof. A. had before seen unmistakable traces of drift in the 
Province of Rio and in Minas Geraes; but ewe was everywhere con- 
nected with the drift itself such an amount of decomposed rocks of vari- 
ous kinds, that it would have been difficult to satisfy any one not familiar 
with drift that there is here an equivalent of the northern drift. There 
is found at Tijuca the most palpable superposition of drift and tn decom- 
posed rocks, with a distinct line of demareation betwee n the 
This locality afforded an opportunity of contrasting Oke ees omposed 
-Tocks, which form a characteristic feature of the whole country, with the 
n- 
te, gneiss, mica slate, clay slate, in fact all A age various kinds of rocks 
Hein found in old ee formations are si uced to a condition 
ks a 
of rocks. 
The wh @ passes u mis Here to rocks of the same kind in whieb the 
hatte or disintegration is only partial, or no trace of it is visible, 
and the whole mass exhibits then the appearance of a set of or 
Au, Jour. Sct.—Seconp Serres, Vou. Xk, No. 120.—Nov., 1865. 
50 
