Ii6 The 'American Geologist. August, 1 899 
America, Europe and Asia, have been found in bogs mingled 
with boulders and gravel.* 
This, the Tertiary period, is subdivided into three epochs, 
the earliest of which is sometimes found to merge into preced- 
ing tropical conditions through a 'Transition epoch," although 
generally the passage is "non-conformable." A marked char- 
acteristic of the record made by Nature's thermometers — veg- 
etable and animal life — is that the temperature was practically 
uniform through the whole range of the present widely varying 
zones of life.t 
The life in Siberia recorded the same temperatures as that 
on the shores of the Mediterranean; life in Alaska was of the 
same nature as that in Brazil or Patagonia; so that the fact is 
of record that there were no zones of temperature — particular- 
ly was this the case with marine fauna and flora. ;J; 
The Tropical and Torrid Ages. 
During the Mesozoic and Paleozoic ages there existed 
much warmer temperatures than we have just reviewed for the 
Temperate age. It would be useless to cite, to even the young- 
est students of geology, the facts which could be massed to 
prove the universal distribution of the tropical plants of the 
Carboniferous age § or of the warm water marine life of the Sil- 
urian age. II 
The manuals and text-books of geology are overburdened 
with instances and illustrations. Underneath the strata of 
these ages lie the previous strata of the Cambrian and Lauren- 
tian, beneath which lie in turn the enormously thick, non-fos- 
*Journal of Geology. Vol. I, No. 8, p. 767, as previously quoted. 
In citing biological evidence tending to show that Brazil has never 
been glaciated, Prof. Branner fails to explain how or why these 
animals became extinct — although he attempts to show in the face of 
his own observations to the contrary, that there has been an unbroken 
succession in tropical life in Brazil since the Tertiary (p. 770 of work 
cited). 
This extinction occurred since the Tertiary. It is at least probable 
in the absence of definite proofs of some other cause, that these ani- 
mals became extinct about the same time and through the same 
agencies by which corresponding life became extinct elsewhere. 
tSee also Dana's Manual of Geology. 1895. p. 939. 
J Manual of Geology, Dana. 4th Ed., p. 872. 
§Manual of Geology, Dana, 4th Ed., p. 711. 
il Manual of Geology. Dana, 4th Ed., p. 574. 
