364 The American Geologist. December, 1894 
little or no difficulty in accounting for most of the things that 
now puzzle us in connection with other seams; but I am 
rather afraid, unless a larger number of competent observers 
take up the working out of the geology of the "Pittsburg 
bed" than seem to be now so engaged, the seam itself will be 
about all "worked out" ere the problems which confront us 
are settled. 
Anent this coal seam question it should not be forgotten 
that, as yet, the form Stigmaria (in any of its various phases) 
has not yet been reported in connection with it.* This cir- 
cumstance alone casts reasonable doubt as to its growth in 
situ, origin, or formation, as usually understood. Moreover, I 
find its floor or under bed (that of the 22-27 inch bench of 
coal forming the basal member or division of the seam) to be 
a calcareous shale, wherever I have examined it, carrying very 
numerous remains of an aquatic fauna. 
The extraordinaiy uniformity of the Pittsburg bed as to 
purity and structure of coal, evenness and geographical ex- 
tent of its various strata, its widespread interstratified shales 
and the marvelous persistency of them, and other characteris- 
tics, make this seam, in its entirety, the most remarkable, most 
typical, most interesting one of which we possess any knowl- 
edge ; it is probably the most extensive instance of horizon- 
tally or parallelism in stratification any geologist in any 
country ever did or ever can point to. It is certainly phenom- 
enal ; and yet I maintain that a rational explanation of any of 
its individual layers, from and including underbedto topmost 
member, has y^et to be found. About all that can with safety 
be said about it is that, everything being horizontally strati- 
fied, every part of it was most likely accumulated under 
water. I have therefore come to the conclusion that this coal 
bed is the accumulated remains on the bottom of a lake or 
•sea of vegetable growth of aquatic forms \ (though much of it 
did not necessarily grow in the water) living afloat and dying 
and decaying, falling through the water. J I do not recollect 
*The only fragmenl at all resembling Stigmaria I have seen or heard 
of frum the Pittsburg horizon was one found l>\ myself near Elizabeth. 
Pa., on a bit of a shale hinder in lsni. 
(•Vegetation of such character as thrived in luxurianl profusion upon 
the surface of the water. 
[See Quart. Journ. Geol. Soc. of London for August, 1894. 
