The Taconic or Lower Cambrian. — Winchell. 
295 
From the review of the ghieial and interglaeial stages shown 
by interbeddecl till and fossiliferous formations in North 
America, which has been attempted in this paper, the rela- 
tionship of the minor time divisions of the Glacial and Cham- 
plain epochs, under the helpful new nomenclature of Cham- 
berlin, may be formulated provisionally as follows, the order, 
as in the former table, being that of the stratigraphy, so that 
for the advancing sequence in time it should be read upward. 
Epochs and Stages of the Glacial jieriod. 
r 
Champlain epoch 
(Land depression; 
disappearance o f 
the ice-sheet; re- 
elevation of the 
land.) 
Glacial epoch 
(Ice accumulation, 
due to the culmina- 
tion of the Lafay- 
ette epeirogenic up- 
lift.) 
Wisconsin stage 
(Progressing re-el- 
vation.) 
Champlain subsi- 
dence 
Iowan stage. 
Interglacial 
stage 
I 
I Kansan stage.. 
I 
I 
Moderate re-elevation of the land, advan- 
cing as a permanent wave from south to 
north and northeast; continued retreat 
of the ice along most of its extent, but 
its maximum advance in southern New 
England, with fluctuations and the for- 
mation of prominent marginal moraines; 
great glacial lakes on the northern Doi- 
ders of the United States; slight glacial 
oscillations, with temperate climate 
nearly as now, at Toronto and Scarboro'; 
the sea hnally admitted to the St. Law- 
rence, Champlain. and Ottawa valleys; 
uplift to the present hight completed 
soon after the departure of the ice. (The 
Great Baltic glacier, and European mar- 
ginal moraines.) 
Depression of the ice-covered area from its 
high Glacial elevation; retreat of the ice 
from its former Iowan limits; abundant 
deposition of loess, 
f Renewed ice accumulation, covering the 
! forest beds and extending south ;iearly 
I to its early boundary. (Third European 
I glacial stage.) 
r Extensive glacial recession in the upper 
I part of the Mississippi basin; cool tem- 
I perate climate and coniferous forests up 
1 to the waning ice border; much erosion 
I of the early drift. 
Ma.\imum extent of the ice-sheet in the in- 
terior ot North -America, and also east- 
ward in northern New Jersey. (Maxi- 
mum glaciation in Europe.) 
Undetermined I 
I STAGES I 
I of fluctuation in the 1 
I general growth of I 
I the ice-sheet. L 
Including an early glacial recession and 
readvance in the region ot the Moose 
and .Albany rivers. (I'irst glacial stage 
in the Alps.) 
[Crucial points in the geology of the Lake Superior region. No. 3.] 
THE ERUPTIVE EPOCHS OF THE TACONIC OR 
LOWER CAMBRIAN. 
By N. II. Winchell. Minneapolis, Minn. 
It is desired here to make it plain that the eruptive rocks 
of the Taconic, or Lower Cambrian, can hardly be confounded 
with those of the Archean. There may be some difficulty in 
distinguishing the one from the other in England and Wales, 
