L. Lesquereux on the Coal Formations of North America, 21 
Art. IIL. nae some questions concerning the Coal Formations of 
North America; by L, LESQUEREUX. 
Ir may perhaps be said that as everybody is now acquainted 
with the coal, with its essential constituents and the general laws 
of its formation, an attempt to offer to science something new 
or even —— on the subject, must prove a fruitless task. 
This assertion has a semblance of truth only, for it is certain 
that nas of the various and most important phenomena con- 
nected with the formation of coal are not satisfactorily, nor even 
at all explained. And as they are continually brought forward 
for discussion, either by lecturers or systematic geologists, the 
subject of the formation of coal, considered as a whole, has been 
obscured in such a manner that it is doubtful if the most essen- 
tial facts on the subject, some of which may be considered as 
demonstrable, are not still looked upon by many as hypothetical 
and individual opinions. It is with these peculiar phenomena 
of the coal formations, and consequently with the exposition and 
the discussion of geological facts connected with them, that we 
have to deal in the first part of this paper. 
As we cannot expect to come to a right understanding of the 
formation of oe without some acquaintance with the vegetation 
of w ns it is made, our attention must necessarily to 
some extent be: eines to the flora of the coal period. But it 
is not enough to — the peculiar nature, the anatomical and 
ts. stu 
them also in their arti graphical distribution, in the different oa 
basins of America and of other countries, and also in the suc- 
cessive strata of the coal at different geological horizons. And 
it would be desirable also to examine the vegetation of the coal 
in conneetion with other external influences, in order to become 
acquainted if possible with the climatic conditions that prevailed 
at the time of the coal formation. 
The plan _ we propose to follow may aecidentally direct 
the diseussio some points which do not 4 to have a 
close relation to re formation of the coal. But we must bear 
in mind that geological eras are not very Sictinetly limited ; or 
at least _ oe _— a true understanding of one ~! them it is 
es to examine the causes that ep = 
