1<> The Aliit'nrdn GeoliXJixt. .iMiiniry. 18!« 
judfiiiHMils ill t 111' |ii-('inis('s. No one w lio ludds the \ it'w thii( thf>re 
\\ ere t w o or iiiort' ulaciiil ('|)oclis (•;iii (•oiii|ii;iiii tli;it our aiitlior at- 
t(Mii|)ts to inci'l tlicir arfiiiiiueiils. liiK tliev could wish lliiit lie had 
jjivcii tlit'in more a|>|)r(H'iiiti\(' and iiiorc ath'(|ual<' i-oiisidcrat ion. 
Tins much al least was due liis ivaders. It docs not seem to us that 
the ai'jiumenis for more than one ice-epoch arc at all met in any single 
instance. No point is ur^^cd atiainsi di>tincl cpoclis. w jiicli the be- 
iie\('i-s in recurrent epochs lia\e not careruilv considered, and re- 
yarded as insuliicient to ovcrliahince liie positi\e evidence on the 
otlier side. 
If we nii(h'rstaiid t lie ariiunients w liicli lia\ e been adduced for more 
than one glacial ei)ocli. Prof. Wiiglit has altogether ignored one of 
the strongest of them, unless his third point (|). MS) is a misinterpre 
ration of it. He rel'ers to tlie "argument for two distinct glacial peri- 
ods, (we presume he means epoelis) drawn Ironi tlii' smaller apparent 
amount of glaci.-il erosion oxer the soiilherii ))art of glaciated area. 
■"• ■••■ ••■■ •■•• " .\s wc understand the erosion argument, the above 
does not touch it. The argument is this: The older dril'r sheet (as 
interpreted iiy most giacialists who h;i\e studied it) iin'^ xii(l'rn'il tiiiich 
'ituirc Kiihiiiriiil criisiiiii siiiri' it iriix hiiil i/iiKii than has the newer drift 
sheet; — many giacialists would say several times as much. This is 
the only erosion argument we have known to be especially ui'ged in 
sui)port of two ice-ej)ochs. and this our author does not touch. 
Since the idea of more than one ice-epoch began to receiNc cai'eful 
attention, the drift of opinion seems to have been towards its accejjt- 
anee. both in .\merica and in Kurope. So far has this gone, that in a 
])ai)er just published. Prof, .lames ( ieiUie goes to the extreme (as it 
would seem To many) of mai)piiig the ice of the fourth glacial ei)()ch 
in Europe, and believes there was at least a lifth. In this particular 
therefore, the volume can hardly l)e said to represent "t he present 
state of progres.s." 
In the course of his consideration of the :irguments for two glacial 
epochs. Prof. Wright indicates that the oceanic waters |)rol)ably 
reached southern Illinois and Indiana during the time of loess dei)osi- 
tion, (p. 120). 1 low this conclusion is reached wc are not told. The 
fossils of the loess would seem to be conclusive evidence against it. 
AVe are further told. (p. M.'J) that the probable cause of the ice-e])ocii 
Avas a late T(M-tiary or post -Tertiary elevation. \\'liile this is a com- 
mon view, there seem to us to be unanswered and unanswerable 
arguments against it, and if we are not mistaken the ])resent drift of 
opinion is away from it . 
In this connection, too. \\ e liavc a sir.-inge ■■well-known law of 
})arsimony"' slated, a law ■"which re(|uires us in our e\i)lanatlon of 
phenomena to bi' content w it h t lie least cause which is sullicient to 
])roduce them," ai>])arent,ly wit lioiil regard to its truth. This is cer- 
tainly a curious law . 
In the chapter on drainage systems in the glacial ])eriod.we read 
again of the hyjxit het ical glacial lake caused by tlie hypothetical ice- 
