The L'Anse sentinel., 1921-05-13

eral matter. All are readily distin-
guishable In the photomicrographs.
Examination of number of Goals
has shown that most of the coal is de-
rived from the woody parts of plants,
such as trunks. stems, branches and
roots. including all the tissues that
make up such parts. Some of this
wood Is represented by the larger an
thraxylon, some by the smaller an
thraxylon and some by the attritus.
The proportion represented In each Of
these varies In different Goals and even
at different levels in the same coal
bed. There is evidence that some of
the cellulose matter is derived from
the more delicate tissues, such as her.
baceous plants, young or growing parts
of plants, leaf tissues, etc. ~
The humic or decayed vegetable mat
ter forms considerable proportion OF
the attritus OF all Goals. 1t is derived
from the cellulosic parts of plants, but
! includes, besides macerated, seml-de-
cayed wood. some macerated gum,
bark, pith, cortex and other more deli
cate parts. There Is no sharp dividing
line between the anthraxylon and the
humic constituents.
Resins are found In all Goals, but In
greatly varying proportions, both In
the anthraxylon and the attritus. When
found In the anthraxylon. the resin Is
found In those tissues where 1t would
be expected IL the constituent were
still sound piece of wood. In the
attritus the resins are easily distin-
guished from the other constituents.
Comparing Different Goals.
The exines or outer walls of spores
are present In the attritus only and
form an important part Of all Goals,
but in greatly varying proportions. The
spore exines are the most readily dis
cernible constituents In all Goals. and
have definite characteristics. Different
genera and perhaps different species
of exines differ In sculpturing. size,
form and thickness of wall, and by
means of these characters can readily
be distinguished from one another.
The spore characters have been so well
spores of-one kind Of plants can b0
clearly distinguished from those Of an
other kind. In some coal seams the
larger bulk of the spore exines are of
the same kind, in other seams two or
three kinds may form the main bulk.
In comparing Goals from different beds
the predominating exines Of one seam
are easily seen to be different In some
way from those of any other bed. Thus
the Goals of different beds, containing
different spores, may readily be dis
tinguished from one another.
Occasionally In given coal seam a
spore exine Is found that differs from
those of any other seam, but does not
predominate. This spOre exine may be
distinguishing characteristic of the
coal seam in question, although not the
predominate one. This fact promises
to be of value In the stratigraphic cor
relation of coal seams. The Pittsburgh
seam, for example, contains small
spore exine that is both predominant
and Characteristic and may thus be
easily distinguished from any other.
tain certain constituents that are more
highly carbonized than the rest of the
coal and stand out in sharp contrast
to II on account of their opaqueness.
In general there are two types Of car
bonaceous matter-one type shows def
mite plant structure and consists of
the more highly carbonized parts Of
plant cells or bits Of woody tissues or
other plant tissues; the other shows
no plant structure and is Of indefinite
origin.
Other constituents that are invari-
ably present In all Goals are the So
called rodlets or needles. Many are
scattered helter-skelter through the at
tritus. Sometimes they are present In
such large numbers that they form a
considerable part Of certain thin Iami-
nae. Many Of the anthraxylon compo-
nents, and. conspicuously. many of the
mineral charcoal constituents, inclose
smaller or larger number ofrodlets
that are evidently part Of their struc-
ture. Most of the tissues remaining In
the coal with which rodlets are associ-
ated are recognized to be those OF
plants related to the Medullosne, we'll
known paieozoic plants allied to the
cycnds. From This 1t appears that
some OF the rodIets, II not all. are the
semI-petrified contents Of the mucilnge
canals OF MedulIosa-like plants. In the
original plants these canals were elon-
gated intercellular spaces containing
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