J'crsoiKif (!//(/ Scifiil i fir Xcirs. 
'l^)i 
molkiscini shells, enclosed in beds uiiderhiin and ovi-rlain by till. Sucii 
lliicluations, wliile Ibe ice accumulalion was in prou'i-ess. enclose cliietlv 
arctic or boreal species: but when liie ice was beini;- melled awa\. in 
the Cham plain epoch, the remains of tiie Hora and fauna I litis occurrini^- 
in interjilacial beds, as at Toronto and Scarboro'. Out., mav Ijeloni;- 
wholly to tejiiperale species, such as now exist in the sanie district. The 
cold climate of the Ice a<;e appears thus to Iia\ e l)ee!i followed by a tem- 
perate C'hamplain climate close upon the waniiiii- ice-bordej-. 
From this rev lew of the drift deposits and of the cliniai ic and ulacial 
oscillations. Mie minor time divisions of the Ice aye are tabulated pro- 
visionally as follows, in accorchmce with the noineiiclal ure for the iila- 
cial sta,ij('s which is proposed l)y Chamberlin in the iiewedit ion of (Jeikie's 
■'(ireat Ice Aij'e." Tiie t wo stages of growth of tin' ice-sheei may lune 
been due. aside from their principal dependence on the hiuh ele\alion 
of the land, to the climatic elfecls of 1 he lasl two passages in the ]>ie- 
cession of the e({uiiio\es. with accompanying niilation. l)rinL:i iiu' tin' 
wintersof the northern hemisphere in aphelion about lilJ.dOd \ I'.-irs au'o. 
and aii'ain about lO.dOU \ears a^o. 'I'liis explanat l<iii, which may be 
u'ood iii-ound for a compromise between the hitely opposiiiii \iews of 
unity and of dualit\' or ^ireater comidexity of the (ilacial pc-iod. agrees 
with Prof. X. H. Wiiicheirs well known (•(Jinpiitat ions from the rale of 
recession of the falls of St. .\ntlioiiy fortlw I'ostulacial or Itecent pt-- 
i"iod, aiul with bis estimate of the duration of the lntei-i:laci;d stai^e 
(Am. GE()l,()(iTST, vol. X. jip. (ii)-S(i. with sections and map. .\ni:'. IS'.Ci) 
from the now bui'ied channel which appears to ha\e Ihtii iImmi eroded 
by the Mississippi ri\ei' a few mili's west of the present udriie lidow 
these falls. The ordiM- of the table is strat iijraphic. so that foi- the se- 
(|uencr in time it should l)e read upward. 
t:r( 
AM) Stages 
CnAMPLAIN KPOCn 
I Land depression; 
disappearance o f 
the ice-sheet; par- 
tial re-elevation of 
tlie land, i 
Wisconsin stage 
I Progressing re-el- 
evation. I 
Chami'i.ain 
DENCE 
loWAN stage. 
Glacial epoch 
(Ice accumulation, 
due to the culmina- 
tion of the Lafay- 
ette epeirogenic up- 
lift. I 
Intergi.acial 
STAGE 
K.-VNSAN sr.\(;i-: 
Uni)ETEkmim-.1) 
STAGI-;s 
of fluctuation m the , 
gener;il growtli of | 
the ice-sheet. 
THE Glacial 1'I-:rioi). 
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 
maxinnim advance in southern Xew 
Laiglaiid. with tiucliiations and the for- 
mation of prominent marginal moraines; 
great glacial lakes on the northern bor- 
der of the L'nited State.-; slight glacial 
oscillations, W'ith 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 higlit completed 
soon after the departure of the ice. 
Depression of the ice-covereil area from its 
high (ilacial elevation; retreat of the ice 
from its former lowaii limits; abundant 
deposition of loess. 
Renewed ice accumulation, covering the 
forest beds and extending south nearly 
to its early boundary. 
Extensive glacial recession in the upper 
part III the Mississippi basin: cool lem- 
l)er;ite climalc and coniferous forests 
up to the waning ire border; mucli ero- 
sion of the early drift. 
Maximum extent of tlie ice-sheet in the in- 
tirior of North .America, and also east- 
w;irtl in northern New Jersey. 
Including an early glacial recession .ind 
reiidvance, as sliown by interglacial beds 
of lignite, in the region of the Moose 
and .Mliany rivers, tributary to James 
)av. 
IM'of. 
\{. 1). 
S.M.I 
■eferre. 
il the 
lerni 
■ lit i!V. in discusbion of 
"ici' iii\ ;ision.'" r\cn for 
\\\r 
tin 
two precedjni 
ylacial sla.iio 
papers, 
marked 
