Correspondence. 331 
views once formulated should prevent us from adopting- Geikie's lead- 
ing. Indeed, he almost makes this reference himself, in his comments 
upon Prof. Chamberlin's preliminary correlation (page 774). He first 
identifies the Kansan stage with his second glacial epoch, and then asks 
whether there is not some deposit that can bo correlated with the Wey- 
bourn crag, saying that "patches of *old drift,' as we have learned, oc- 
cur here and there buried under the accumulations of the Kansan 
stage." No one who has been familiar with the discussions of Ameri- 
can geologists during the past forty years can fail to perceive that the 
Lafayette terrane is the deposit occui)ying this place, as it is both late 
Pliocene and glacial. It is true that Tuomey and Hilgard referred it to 
the Quaternary, but that was upon the assumption that the entire Ice 
age belonged there. If anyone hesitates to call the Lafayette gravels 
glacial in origin, let him explain how crystalline boulders, cobbles, and 
pebbles, from the northern Arcluean can follow the Mississippi to its 
mouth (Petite Anse). They must have been transported a thousand 
miles, a greater distance than is known for any other glacial debris. 
Further, the late Tertiary was a time of high continental elevation 
for both North America and nortliern Europe, and this has been thought 
to account for the origin of the cold climate. Professer Geikie states 
that every one of his glacial epoclis commences with the land at a high 
stage of elevation. Owing, perhaps, to the weight of the accumulating 
ice, the crust of the earth sinks down, so that the.se epochs end with 
•depression. Do not these facts prove a connection of the cold with eleva- 
tion? And if so, was there any Pleistocene epoch when the conditions 
were more favorable than those of the Lafayette epoch for producing 
the cold? It is possible that tlie fact will be found even more than is 
thus claimed, and tliat the Lafayette may have been the time of maxi- 
mum glaciation. Because of the existence of the Lafayette gravels, I 
liave formany years insisted, in conversation and class instruction, that 
the entire Atlantic and Appalachian highlands were snow-clad at this 
time, the region being truthfully described in Dawson's humorous label 
of Appahichia infelix. Striation has been mentioned as occurring in the 
Virginia or North Carolina mountains by II. P. Stevens, in an old edi- 
tion of Dana's Manual. While I agree with Hilgard and Ui)liam in be- 
lieving the Lafayette beds to have been laid down by torrential streams, 
tho.se who think them estuarine or littoral may be etiually well satisfied 
of the existence of glacial conditions. 
Next let us see aboiit the unity of the Ice age. In the later Pliocene 
the climate in high northern and. southern latitudes became cold enough 
to originate glaciers which have never ceased to exist in the remoter 
centers of dispersion, like tlie Alps, Scandinavia, and some portions of 
both Americas. It is therefore a siufjh' period, characterized by extreme 
and continuous cold. The refrigeration commenced gradually, and af- 
ter a warm interval, culminated in the second or Kansan epoch; since 
which time the colder stages have been less and less extreme. Our win- 
ters, with their alternate s])ells of freezing and thawing, but having a 
culmination about the first of Fel)ruar\-, may illustrati' the vurving con- 
