October 25, 1895.] 



SCIENCE. 



533 



and courses of all storms, was not less mild 

 than now. The trees whose wood is found 

 in the interglacial Toronto beds now have 

 their most northern limits in the same 

 region. 



9. Iroquois stage. Full expansion of 

 the glacial Lake Iroquois in the basin of the 

 present Lake Ontario and northward, then 

 outflowing at Rome, N. Y., to the MohaAvk 

 and Hudson rivers. Gradual reijlevation 

 of the Eome outlet from the Champlain 

 subsidence had lifted the surface of Lake 

 Iroquois in its western part from near the 

 level of the present lake at Toronto to a 

 height there of about 200 feet, finally hold- 

 ing this height during many years, with the 

 formation of the well developed Iroquois 

 beach. 



Between the times of Lakes Warren and 

 Iroquois, the glacial Lake Lundy, named by 

 Spencer from its beach ridge of Lundy's 

 Lane, probably had an outlet east to the 

 Hudson by overflow across the slope of the 

 highlands south of the Mohawk ; but its 

 relationship to the glacial Lake ISTewberry, 

 named by Fairchild as outflowing to the 

 Susquehanna by the pass south of Seneca 

 Lake, needs to be more definitely ascer- 

 tained. 



10. St. Lawrence stage. The final 

 stage in the departure of the ice sheet which 

 we are able to determine from the history 

 of the Laurentian lakes and St. Lawrence 

 valley was when the glacial Lake St. Law- 

 rence, outflowing through the Champlain 

 basin to the Hudson, stretched from a strait 

 originally 150 feet deep over the Thousand 

 Islands, at the mouth of Lake Ontario, and 

 from the vicinity of Pembroke, on the Ot- 

 tawa river, easterly to Quebec or beyond. 

 As soon as the ice barrier was melted 

 through, the sea entered these depressed 

 St. Lawrence, Champlain and Ottawa val- 

 leys ; and subsequent epeirogenic uplifting 

 has raised them to their present slight alti- 

 tude above the sea level. 



Later stages of the glacial recession are 

 doubtless recognizable by moraines and 

 other evidences, the North American ice 

 sheet becoming at last, as it probably also 

 had been in its beginnings, divided into 

 three parts, one upon Labrador, another 

 northwest of Hudson Bay, as shown by 

 Tyrrell's observations, and a third upon the 

 northern part of British Columbia. From 

 my studies of the glacial Lake Agassiz, whose 

 duration was probably only about 1,000 

 years, the whole Champlain epoch of land 

 depression, the departure of the ice sheet 

 because of the warm climate so restored, 

 and most of the reelevation of the unburd- 

 ened lands, appear to have required only a 

 few (perhaps four or five) thousand years, 

 ending about five thousand years ago. 

 These late divisions of the Glacial period 

 were far shorter than its Kansan, Aftonian 

 and lowan stages ; and the ratio of the 

 Glacial and Champlain epochs may have 

 been approximately as ten to one. The 

 term Champlain conveniently designates the 

 short final part of the Ice age, when the 

 land depression caused rapid though waver- 

 ing retreat of the ice border, with more 

 vigorous glacial currents on account of the 

 marginal melting and increased steepness 

 of the ice front, favoring the accumulation 

 of many retreatal moraines of very knoUy 

 and bouldery drift. 



Warren Upham. 

 Cleveland, Ohio. 



HELIUM AND ARGON. 



Brief accounts of the discovery of helium 

 and argon have already appeared in the 

 pages of this journal. More recently, sev- 

 eral important observations have been made, 

 which, while not establishing with certainty 

 the nature of these substances and their 

 places in the system of the elements, at 

 least afford a reasonable basis for specula- 

 tion. 



Helium was originally obtained from the 



