Personal uixl Scientific fiTeios. 199 
Tertiary and early Quaternary Baseleveling in Minnesota, Manitoba, and 
Nbrthtcestward. Warren Upham, Somerville, Mass. The ureal north- 
western plains have an approximately flat surface which has been low- 
ered by Tertiary baseleveling 500 to 3,000 feel below the original surface 
of the Laramie and Montana strata as they were at the end of the Cre- 
taceous period. Measures of this general erosion are supplied by the 
Co tea u des Prairies, the Turtle mountain, and numerous other isolated 
hill and mountain areas upon the country reaching thence west to the 
Rocky mountains. 
Near the end of the Tertiary era and in the early Quaternary, the 
eastern part of this vast baseleveled expanse was deeply eroded and 
newly baseleveled, the resulting lower plain being the flat area of the 
Red river valley, averagingSO miles in width, and of the wider Manitoba 
lake region. The depth of this later immediately preglacial erosion was 
300 to 1,000 feet, as shown by the Pembina mountain and the Manitoba 
escarpment, which extends thence northward along the west side of the 
great lakes of Manitoba to the Saskatchewan river. The chief topo- 
graphic features of Minnesota and Manitoba have been produced by 
these cycles of baseleveling, especially by the latter which was due to a 
great uplift of the region terminating in the Glacial period. 
Departure of the Tee-sheet from the Laurentian Lakes. Warren Up- 
ham, Somerville. Mass. Beaches and deltas observed in the vicinity of 
Duluth are referred to (1) the Western Superior glacial lake, outflowing 
southwest ward across the divide between the Hois Brule and St. Croix 
rivers in northwestern Wisconsin; (.2) the glacial lake Warren, outflow- 
ing southward by Chicago to the Des Plaines, Illinois, and Mississippi 
rivers; and (3) the glacial lake Algonquin, outflowing by the St. Clair 
and Detroit rivers, and along the bed of lake Erie, to the incipient Ni- 
agara river and glacial lake Iroquois. The extent of high stages of lake 
Warren, shown by beaches around lake Superior and east ward to lake 
Nipissing and to the east end of lake Erie, traced and mapped by Tay- 
lor, Gilbert, Spencer and others, implies thai the ice-sheet had retreated 
from the northern border of the United Stales as far eastward as to 
the angle of the drill boundary near Salamanca in southwestern New 
York, while ye1 the urea t lobe of this ice-sheet easl of Salamanca re- 
mained upon New York, northeastern Pennsylvania, northern New 
Jersey, and New England. This unexpected view of the order of reces- 
sion of t he ice-sheet is found explainable by t he meteorologic condil ions 
of abundant snowfall at the easl brought by storms saturated from I he 
melting ice surface al the west. The paper also traced the historj of 
the Niagara river, which is thoughl to afford a measure of the Postgla- 
cial period as about 7,000 years, and called attention to the expansion of 
lake Iroquois northward and northeastward until iis waning ice-barrier 
was finally melted away from I he Si. Lawrence vallev near Quebec, I hen 
admitting the sea to the Si. Lawrence. Champlain, and Ottawa valleys. 
The Extension of Uhiformitarianism to Dtformatinn. \\\ \\ .1 McGee, 
Washington, I). ('. .Many shores, like thai of Holland, are subsiding al 
a considerable rate; yel no horizontal movement accompanies the sub- 
sidence. Man.v coasts, like thai of Scandinavia, areskirted b\ elevated 
beaches indicating recenl emergence; yet there is nothing to indicate 
and everything to disprove coincident lateral movement. .Main dis- 
tricts, like thai of the Laurentian lakes, are traversed bv ancienl 
strands, provingnol onlj vertical movemeni butdecided warping in the 
earth's crust; ye1 no record of accompanying horizontal movemeni 
is found. The COaStal /ones of llle Colli i lien Is a re made up of series of 
formal ions and unconformities recording wide vertical oscillation of the 
land will) respect in the sea: yet little evidence id' horizontal movement 
has been detected. About one-fourth of the land of the earth is moun- 
