314 J. E. Teschemacher on the 
sembling that of the vegetables of the present day, may pos- 
sibly have varied considerably in the time and the manner of 
their growth ; and, although we have yet no data on which 
to found calculations, there is no reason why the growth and 
development of the vegetable might not have then been as 
extensive in one year as it is now in many. While several 
reflections on the little we know concerning the internal 
organization of fossil plants seem to favor the idea of a rapid 
growth, I am not aware of any which militate directly against 
it; but a lengthened discussion thereon, in the present state 
of our knowledge, would perhaps be premature ; I shall, there- 
fore, pass it over until a future opportunity. 
Professor Pictet, in his lately circulated discussion on the 
distribution of animal fossils, propounds several generalizations, 
or laws. The fourth of these is as follows: 
“ The species which have lived in ancient epochs have had 
a more extensive geographical distribution than those which 
exist in our days." 
The study and comparison of fossi] vegetables seems, even 
at this early stage, to point to an almost universal distribution 
of the same genera and species during the period of the coal 
formation ; and as the opinion seems generally to prevail that 
the plants of which the coal is composed grew where they are 
now deposited, the same conditions, climate and atmosphere, 
under which they vegetated, must have existed throughout 
the whole area, wherever coal-fields are found. 
If, by means of the study of fossil vegetation, we can arrive 
at conclusions favorable to the existence of an extensive unt 
formity of climate, and an atmosphere differing in density as 
well as in temperature from the present, points of much inter- 
est are gained in the important geological question of the 1n- 
tensities of action during the early epochs of the globe, —? 
question on the discussion of which probably hangs the fate 
of most of the theories of the day. 
In establishing a nearly universal (tropical) climate by the 
discovery, in large and distant areas, of the same genera and 
