L. Lesquereux on the Coal Formations of N. America. 379 
each other. At the point where the roots branch and diverge 
from the trunk, the double scars become more and more separate, 
more irregularly placed, and thus the roots take somewhat of the 
appearance of Stigmaria. e difference is well marked, never- 
theless ; the scars being triangular, marked in the center by a 
deep point only, and the roots quickly diminishing in size and 
terminating in a point at a short distance from the base of the 
tree. The imbedding shales not having been preserved, there is 
no trace of rootlets. us ave here, at this high position 
in the coal measures, a new typical form which probably indi- 
cates a difference of vegetation in the subsequent and last stage 
of the coal formations. ett 
This enumeration is already too long, and though still incom- 
plete, it must be abruptly closed, for fear of becoming tedious to 
the reader. In order to be understood by those who are not 
acquainted with botanical paleeontology, it is only necessary to 
sum up and briefly discuss some of the conclusions which are 
derived from this examination. ; 
_ Considering its generic distribution, the American coal-flora 
-isnearly related to the European. We have only two or three 
peculiar genera, representing distinct types, which have not been 
seen in Kuro n the contrary, Europe has no peculiar and 
true generic types of coal-plants which are not represented in 
the coal-fields of the United States. é 
Considering its species, a more marked difference in the coal- 
flora of both continents becomes evident. Some of our species 
been found in its coal-measures. 
—— eet or distinctly characterized forms, belongs to our country. 
Bil 
ph 
pean congeners that their specific ch 
established, : : 
Though further researches ought necessarily to increase the 
humber of species of fossil pl 
the proportional difference is 
ado 
The fossil fore appears identical at the same geological hori- 
 20n, over the whole extent of our coal-fields. This proves uni- 
_ formity of stratification and geological unity of the different coal 
basins of America. 
* The distribution of the genus Lepidodendron, at 
analogy 
the time of the formation of 
the coal, has some with that of the Oak in our time. 
