Correspondence. 139 
Angelo Heilprin ; An account of the Vincelonian volcano, Benj. Sharp. 
Bulletin of the Santa Barbara society of Natural History. Vol. No. 2. 
Iowa Cin. Soc. Nat. Hist., Oct., 1890, contains : New and little known 
American paleozoic ostracoda, E 0. Ulrich ; Concerning a skeleton of 
the great fossil beaver, Castoroides ohioensis, Joseph Moore. 
Transactions, N. Y. Acad. Sci. May-June, 1890, contains : By Geo. F. 
Kunz. descriptions and notes on the following meteorites, Kiowa, Bridge- 
water Burke Co., N. C, Blount Co., Ala., Rutherford Co., N. C, Hay- 
wood Co., N. C, Winnebago Co. Iowa; The change in our climate and 
the cause, E. B. Dunn. 
3. Papers in Scientific Journals. 
Canadian Record of Science, Vol. IV, No. 3, July, 1890. The Quebec 
Group of Logan, Sir William Dawson. 
Am. Nat., Dec. No., The naticoid genus Strophostylus, Chas. R. Keyes. 
School of Mines Quarterly, Nov. Outbursts of gas in metalliferous 
mines, Barnett H, Brough : Examination of mines, H. S. Monroe. 
CORRESPONDENCE. 
Was Lake Iroquois an Arm of the Sea? During the meeting of 
the Geological Society at Washington, I learned from professor Spencer 
that I had confused his lake Iroquois with his lake Algonquin, in my 
note to your journal a month ago. If I now understand him correctly, 
it was lake Algonquin that stood at the higher level, uniting the basins 
of Erie and Ontario; while lake Iroquois was the reduced body of water 
in the Ontario basin, after the separation of Algonquin into two parts. 
Professor Spencer's contention is that Iroquois was at sea-level, and not 
held up above sea-level by a barrier of ice in the lower St. Lawrence 
valley. My note should therefore have referred to the outlet of the 
Iroquois waters past Rome, N. Y.. down the valley of the Mohawk. 
Mr. Gilbert's observations seem to prove the existence of such an outlet, 
and I wished to know how professor Spencer explained it on the suppo- 
sition that Iroquois was an ami of the sea. 
But this question is answered in a paper by prof essor Spencer in tin- 
American Journal of Science for December, to which he referred me and 
in which he says: "Even the coincidence of the shallow and small chan- 
nel, discovered by Mi'. Gilbert, connecting the [roquois waters with the 
sea by the Mohawk valley, or of the broader and lower valley of lake 
Champlain, does nol prove the necessity of a former barrier across the 
St. Lawrence valley, any more than the narrow channels among the 
