Causes and Conditions of Glaciation. — Uphctm. 13 
be melted away, it is objected that the Pliocene and Pleisto- 
cene marine deposits of portions of the shores of Great Brit- 
ain leave no room for such changes there in the relations of 
land and sea. The authors conclude, therefore, that the let- 
age was probably due to great variations in the heat of the 
sun, but how these could be caused is left in uncertainty. 
A second paper, presented to the British Association in 
1893, was by C. A. Lindvall, a Swedish engineer of high at- 
tainments in his profession, whose attention during many 
years of observation has been much given to the problems of 
the glacial drift. His views had been set forth, however, two 
years earlier in a pamphlet of 48 pages, with five plates, pub- 
lished both in Swedish and English at Stockholm in 1891, en- 
titled, "The Glacial Period: essajr on its Origin, Effects, and 
End; as also the Possibility of its Recurrence.'* The drift 
deposition is ascribed to marine submergence with icebergs 
and floes, which are thought to have been borne over Scandi- 
navia, a large portion of Russia, northern Germany, and the 
British Isles, while only the highest parts of the Scandinavian 
plateau rose as islands of the sea laden with the ice of Arctic 
currents. If such submergence should recur, Mr. Lindvall be- 
lieves that an Ice age would be reinstated. Inquiring what 
were the climatic conditions of the earth during its earlier 
eras, he writes : 
We then view our globe in the early dawn <>f time, a glowing mass 
surrounded by a thick veil consisting of almost all the water and other 
volatile matter on our earth, being kept in a gaseous form by the in- 
tense heat. With the intrepidity of youth it cares but little for the 
warmth of the sun, being as hot at the poles as at the equator. Hut 
spite of its covering it loses heat by radiation, and as the earth cools the 
effect of t he sun becomes more and more preceptible First at t he 
poles and so gradually farther down, vegetable life commenced: this 
vegetation being accelerated by the heat of the earth beneath, pouring 
rain from above, and an atmosphere saturated with carbonic acid.— all 
to such an extent thai we can show no parallel; but the product of 
course was luxuriant in due pro port ion During all the periods of 
successive Changes of climate and vegetable life in the polar lands, wil h 
the sole exception of the very latest period, a, more or less broad bell 
has probably existed at the equator which was far too warm for plants 
or animals to exist t here. 
In Falsan's "La Periode Glaciaire" (1889), of which a re- 
view- appeared in the American Geologist for July, L890, an 
