Vol. XXV. No. 5.] 
POPULAR SCIENCE NEWS. 
65 
tlie microscope reveals th<at each filament is made 
up of one hundred or more cells. Thus there are 
|]oni ten to twentj* thousand of these cells In each 
organ, and when it is understood that each of 
tliese cells is capable by union with the germ-cell, 
of rendering the latter fertile, it is seen that 
ample provision is made for the perpetuation of 
tlie species. But what is most wonderful is the 
manner in which these minute male cells are 
brought into contact with the female cell. By 
taking a filament from a ripe antheridium and 
crushing it under the cover-glass of a microscope, 
one can see minute, spiral-shaped bodies issuing 
from the cavities of the cells of the filament and 
swimming iibout in the water. One can scarcely 
resist the impression that these are minute animal 
organisms as they go whirling along through tlie 
water by means of the lashing movements of their 
two long cilia. They consist, however, of nothing 
more than the protoplasm of the filament-cells, 
wliicli has acquired this special form and motile 
property. 
- - a. 
A, portion of chara plant, showing arrangeniont of leaves 
and branches. B, Small portion of stem, showing fruit, a, 
antheridium; o, oogonium; /, leaf; n, uode; ii/ internode 
ceils. 
It is now evident what the use of the chimney- 
like part of tlie oogonium is. ThrougfT the soft 
nmcilage which fills it, the antherozoid, as the 
swimming male reproductive body is called, makes 
its way and so comes into union with the female 
cell. The latter is then capable of developing into 
a new plant ; but germination probably does not 
occur until the next spring. This is the sexual 
method of reproduction in chara. Like the other 
plants we have studied, it is also capable of repro- 
ducing its kiud by an asexual process. At the 
nodes of the central stem, branches of a special 
kind grow out. These become detached from the 
])lant and, acquiring root-hairs, develop iuto inde- 
pendent pliints of the same size and structure as 
those from wliich they were derived. 
Umox College, Schexectauy, X. Y. 
GEOLOGICAL DISTURB AXCES AND CLI- 
M.VnC CHANGES. 
BV JOSEPH WALLACE. 
The most orthodox of our day do no longer 
nestion the vast cycles of time which passed be- 
veen geological formations, and cau readily ac- 
•cept shorter periods between the physical distur- 
bances of the surface of the earth iu the way of 
climatic changes, glaciers, submersion, and eleva- 
tion <luriiig the Tertiary period, which are, so to 
Uay, but drops in the bucket. 
As this period is said to embrace the advent of 
man, the climatic changes which took place and 
wliich gave the higher temperature to the North 
Pole began over two hundred thousand years ago, 
and the seasons of the two hemispheres were re- 
versed every ten thousand five hundred years for 
one hundred and sixty thousand years, so that in 
place of one or two glacial periods, as generally 
supposed, we really had fifteen changes of arctic 
temperature, each change reversing the seasons in 
the two hemispheres. 
As the surface of the earth passed through 
its greatest disturbance at the close of the Meso- 
zoic or Secondary period, it is out of question to 
suppose that man inhabited this globe at that 
time. It is said with some truth that " a thou- 
sand years are not more to a geologist than one 
day from sunset to sunrise." Some are very ex- 
travagant in their statements venturing opinions 
without foundation, and that of man being a den- 
izen of this globe in the Mesozoic period is sheer 
nonsense and ridiculously absurd. 
In order to explain the causes which had led to 
the physical changes of the earth's surface prior 
to or " contemporary with man," we will briefly 
mention those which bear directly on our subject. 
nie Cainozoic or Tertiary period embraces the 
following subdivisions : Eocene, Miocene, Plio- 
cene, and motlern or recent. The close of the Mes- 
ozoic was marked by great geographical changes 
during which the surface bottom of the cretaceous 
sea was raised, partly into land and partly into 
shallow marine and estuarine waters. These 
events must have occupied a vast period of time, 
so that when sedimentation was resumed the or- 
ganic remains of the secondary age entirely disap- 
l)eared except a few low forms of life, and gave 
place to others of a more distinctly modern type. 
nie name Tertiary, given in the early days of 
geology, before much was known regarding fos- 
sils and their history, has retained its hold on the 
literature of science. It is sometimes replaced by 
the word Cainozoic (recent life), which expresses 
the great fact that it is in the series of " strata 
comprised under this designation that most recent 
species and genera have their representations. 
Taking as the basis of clasiflcation, the percent- 
age of living species of mollusca found in the dif- 
ferent groups of the Tertiary series, Lyell pro- 
posed a scheme of arrangement which has been 
generally adopted. Ilis classification is briefly 
this : that he takes it for granted that a deposit 
which contains more numerous species of animals 
still living than .anoth'fer, may be judged on that 
account to be more recent. Such a mode of esti- 
mation is to some extent arbitrary, but in the 
main, when it can be tested by the superposition 
of deposits, it has proved itself reliable. 
The older Tertiary formations in which the 
number of still living species of shells is very 
small, where, in fact, we seem to see, as it were, 
the first beginnings of modern life, he named 
Eocene (dawn of the recent) , including under that 
title those parts of the Tertiary series of the Lon- 
don and Paris basins, wherein the proportion of 
existing species of shells was only three and a 
half per cent. The middle Tertiary beds in the 
valleys of the Loire, Garonne, and Dordogne, con- 
taining seventeen per cent, of living species, were 
named Miocene (less recent). The younger Ter- 
tiary formations of Italy were included under the 
designation Pliocene (more recent), because they 
Contained a majority of from tJiirty-five to ninety 
per cent, of living species. This newest series 
was, however, sub-divided into older Pliocene 
(thirty-five to fifty per cent, of living species), and 
newer Pliocene or Post Pliocene (fifty to ninety- 
five per cent.) This classification with various 
modifications and amplifications has been adopted 
for the Tertiary group, not alone for Europe, but 
for the whole globe. 
AVith regard to the fauna in the Eocene and 
Miocene divisions, we find the greatest develop- 
ment of mammalian forms. Among the oldest of 
these Tertiary beasts are the coryphoden, an ani- 
mal related to the modarn tapirs, and the arcto- 
oyon, a creature related to bears and raccoons. 
These represent, respectively, the pachyderms, or 
thick-skinned mammals, and the ordinary carni- 
vora. Contemporary with or immediately suc- 
ceeding these were species representing the ro- 
dents or gnawing animals with many other 
creatures of the former groups, and allied to ta- 
pirs and hogs, besides other quadrupeds. 
The flora of the Tertiary period is not less re- 
markable than the fauna. The geographical and 
climatic conditions of the northern hemisphere 
were then entirely difterent from those of the 
present day, not ouly iu North America, but in 
Europe, and northward as far as Greenland and 
Spitzl)ergeu, an equable climate prevailed, and the 
abundant plant remains preserved in the Tertiary 
l)eds of those arctic regions show a liixuriaut veg- 
etation like that of the warmer parts of the tem- 
perate zone today. This condition of things was 
of long duration, for iu Europe, as well as in 
Western America, great beds of coal or lignite are 
found in both the Cretaceous and Eocene strata. 
In the Tertiary epoch a distribution of heat is 
discernable In zones, but the decrease of heat to- 
wards the poles was much less marked than at 
present, whilst the tropical zone was probably a 
little warmer than in our day. Central Europe 
during the lower Miocene period had a climate 
nearly equivalent to that of the Southern States of 
.America, or that of North Africa. Under the Arc- 
tic zone, in latitude 78*^ N., the island of Spitzber- 
gen was covered with forests of swamp cypress, 
sequoia (our VVellingtouiana gigantea), many 
kinds of pine, palm, walnut, oak, and lime trees, 
■ — in fact, the vegetation reached to the pole itself, 
if the land extended to it. Since then the heat 
has been diminishing. 
During the early glacial period — for two and 
even more glacial periods are accepted — it sank 
several degrees below the present mean annual 
temperature and continued so for thousands of 
years; then it arose again, and the Swiss lignite 
l>ed8 and the forest beds of the coast of Norfolk 
were formed, and the elephant and rhinoceros in- 
habited these regions. It then fell once more, 
and a second glacial period began ; then it arose 
again, and has continued unchanged ever since. 
What was the cause of the greater heat in the 
Miocene period? Many conjectures have been 
given, some plausible and some far fetched. The 
eminent scientist lleer thinks that this may have 
been from the sun traversing a warmer region of 
space than it moves in now, all regions sharing in 
the great warnith. Dr. Blandet supposes that 
the sun was larger than it is now, the planets hav- 
ing been thrown off from it in its revolution. 
It is supposed that this condition of climate 
continued far into the Pliocene period, but, as this 
went on, a cold climate like that which now char- 
acterizes the northern hemisphere prevailed, and 
gave rise to the glacial phenomena — which will be 
fully explained in subsequent contributions, and 
some new points made known ou the nature and 
origin o^ glaciers, ice-worn or erratic rocks, inter- 
glacial beds, submersion and elevation of vast 
lands during the Tertiary period, volcanos, etc., 
which we trust will be interesting to the readers 
of PopuLAB Science News. 
