Sidc-Light upon Coal Foriuatioii. — Grcslcv. 73 
the axes of the rod. Other rods again have one or two par- 
allel rows of square or box-shaped recesses which may or 
may not contain the yellowish amber or resin. I have ob- 
served these coaly rods in not a few European coals. Cre- 
taceous coals of America also reveal them. They may often 
be seen in the black and gray shales interstratified with coal, 
and in actual contact with fish scales, teeth, etc., and little 
shells. Transverse or vertical sections of coal in which they 
occur reveal them as black dots or shortish lines crowded to- 
gether or scattered, and embedded in grayish material of a dull 
lustre. Bedding planes of coal often reveal these rods in vast 
numbers. Here and there brilliant pitch-coal laminae enclose 
these rods, their presence being detected because of their 
wliite, yellowish amber-like colors. Rods composed of pyrites 
are also well-preserved. Exteriorly these rods are variously 
marked or ornamented; — some partake of the impress of the 
cellular tissues in which they have been formed /;/ situ, others 
are ribbed transversely or fluted longitudinally. In a series 
of illustrations of new(?) plant-structures in coal that I am 
preparing for publication, the relation of these rods to one 
another and to' the rind of the "rod-plant," as I call it, is shown. 
Thus, whatever this rod-plant was, the vast abundance of rods 
in coal — including anthracite, of Pennsylvania, — demonstrates 
that it was very common and very prolific. Another import- 
ant point is this — that since the rods are for the most part 
scattered, broken, fragmentary, or not in place, they were Jiard 
rods before they got into the positions which they now oc- 
cupy. How important this fact becomes when we consider 
the question of the physical and chemical condition of coal 
N (luring deposition or while being accumulated; its original 
thickness or solidity; and the degree or extent of compression 
or diminution in bulk due to weight and compression of added 
strata as the coal measures were piled up, appears evident. 
I'or interesting remarks regarding rods of coal in the great 
"Pittsburg" seam. Prof. D. P. Penhallow's conununication 
i-ntitled "Observations upon some ^tyuctiiral Idriations in Cer- 
tain Canadian Conifene," pp. 26 and 27. Trans. Ro)\ 
Soc. of Canada, Section HI, 1894, may be consulted with 
"l)rofit in this connection. In a ])aper read before the ]\Ian- 
chester (ieological Society, (England) (see Trans. Vol. XX\\ 
