1884. 85 Trans. N. Y. Ac. Séi. 
for luxuriance and variety, was found one species, Liéocedrus decurrens 
(Heer), which is yet living with the redwoods of California; and 
another yet remains on the Andes of Chili, while a third, according to 
Dr. GRAY, is the common taxodium or cypress of our Southern States. 
In Greenland, lat. 70°, were found magnolias and zamias.* All the 
teachings of paleontology, especially as to the earlier periods, are 
that there were then no zones of climate, and that there were warm 
arctic seas all the year round. The evenness of temperature is most 
extraordinary. Such a flora and fauna cannot exist where there are 
great variations of temperature. Yet in these same regions, the sun, 
if the earth’s axis was inclined as now, was shut out for more than four 
months, while for four other months it poured down without cessation. 
Were a four months’ night to settle down now upon the torrid zone, 
the accumulated heat would soon be radiated into space, and when 
the sun returned, no living thing would remain to greet it. 
It will help us to realize the enormous effect, if we remember that the 
cold of our winters in our own latitude is due simply to the change from 
long days of summer to the short ones of winter, plus the change in 
altitude of the sun ; but how much greater would be the cold if the sun 
went for four months below the horizon. 
It may be said that the cold was mollified by the latent heat of the 
surrounding ocean, and by the influence of oceanic currents. But the 
same capacity for giving off heat exists now, and the same currents 
still flow ; yetin Spitzbergen, a not large island, surrounded by a broad 
expanse of water, the cold is most intense. The specific heat of water 
has not diminished; so far as that is concerned, the ocean does as 
much now as then to make the winters there mild, unless there is less 
warm current. The effective cause of Gulf and other streams was 
then, as now, the difference in temperature between low and high 
latitudes. If that were nothing, there would be nocurrent atall. A 
small difference would produce some current, a greater difference would 
produce a more rapid one. And this is true whether the currents are 
due directly to this cause, or indirectly, through the medium of aérial 
currents. In geological times the difference of temperature was much 
less than it is to-day; hence it seems within the bounds of truth to 
say that the ocean currents then were no greater than they are now. 
Whatever warmth-producing influences existed in Spitzbergen and in 
other high latitudes, their effect was no greater in winter than in sum- 
mer. Admitting it to have been as great—a matter of reasonable 
doubt—the temperature, as the days grew shorter, must have fallen 
until it reached a point at which the loss of heat by radiation into 
* Dana’s Man. Geol., revised ed., pp. 514 and 526. 
