. 
Mineratogy and Geology. * $18 
of their transportation in a paper published some years since 
Notes on the Surface Geology of the Basin of the Great Lakes. 
roc. Bost. Nat. Hist. Soc,, 1863), in which it is urged that the 
etn clus sheet of the Erie clays upon which they rest, and which 
than that eines sands, gravels, granite and greenstone bouldere— 
masses of native copper, &c., which compose the superficial Drift 
deposits—have been Jloated to their resting places, = that the 
floating agent has been ice, in the form of icebergs ; ort, that 
these materials have been transported and part be Ge over the bot- 
tom and along the south shore of our ancient inland sea just as 
similar materials ate now being scattered over the banks and 
shores of Newfoundland. 
“If we restore in tly hl this inland sea, which we have 
; ., the northern shore a wall of ice rest- 
ing on the hills of crystalline and trappean foot, ‘abot Lake Su- 
perior and Lake Huron. 
“From this ice-wall masses must from time to time have been 
detached,—just as they are now detached from the Humboldt 
y are 
Glacier -—and floated off southward with the current, b — 
their grasp sand, gravel and boulders—whatever composed the 
beach from which they sailed. Five hundred miles south they 
os upon the southern shore; the highlands of now Western 
ew York, Pennsylvania and Ohio, or the shallows of the prairie 
region of India ana, Illinois a3 Iowa; there melting away and 
depositing their entire loads—as I have gies seen them, a 
thousan es or more boulders on a few resting on the Erie 
clays and looking in the distance like fsck ‘of sheep—or dropping 
here and there a stone and’ sree on east or west, till wholly 
ig 
he Drift grave 
proved all the i sti eozoic rocks of the lake batt, containing their 
racteristic fossils, viz: the Calciferous Sandrock with Maclu- 
rea te Reon and Hudson with Ambonychia radiata, Cyrtolites 
us, Medina with Plewrotomaria litorea, Corniferous with 
Sato pucpepntes Serres, Vou. XLIX, No 145.—Jan., 1870. 
8 
