498 General Notes. [June, 
there have been contentions from time to time, in the literature, 
as to the mode of accumulation of such immense masses of veg- 
etable material, and as to the species of plants furnishing it. In 
his book on Chemical Geology, 1861, Dr. Fred Mohr argues 
forcibly in favor of the hypothesis that the massing together of 
marine algz, or seaweeds, in bays by oceanic currents will account 
for many otherwise inexplicable occurrences of coal beds. This 
view, however, was unable to gain a foothold against the botani- 
cal evidence furnished by the fossil plants so beautifully pre- 
served in the slates overlying the coal beds, and which are terres- 
trial plants exclusively, belonging to much higher organized 
families than the alge. The frequent occurrence, too, of whole 
fossil forests of Sigillarids and Lepidodendroids, rooting in the 
underclay and penetrating the coal beds at right angles, are a5 
many evidences for the swamp hypothesis. Thus far no internal 
coal itself had not been made a part of the argument on either 
with the preparation of microscopic sections of coal. Thus, 
whilst many industrious observers have examined sections and 
noticed the presence of organic structure, no one has ventured to 
interpret what he saw, botanically, because nothing can be seen 
distinctly unless the cutting of the section be proceeded with in 
acertain way. At this point Professor Reinsch steps up with the 
beautiful work now before us. He tells of his microscopic work 
upon the metamorphic limestones of the Huronion, 7. ¢, the 
Eozoon Canadense, the quartz schists and the hornstone concre- 
tions of the Silurian limestones of Ohio; and how he then turned 
his attention upon the coal, and with the previously gained expe- 
rience, soon obtained such remarkable results, that the apparent 
hopelessness of getting satisfaction from the serpentinized and 
silicified structures, was turned into exultation by the carbonized 
material. Here there could be no more doubts, whether the 
things seen under the microscope were sedimentary, concretionary 
or crystalline or organized structures. The results and conclu- 
mineral sections, generally is not serviceable; the cut must be 
less transparent, since the softest parts will be worn faster and 
hence be finally thinner and more transparent than the more 
resisting forms, Sections parallel to the bedding are made with- 
out difficulty. Not so sections at right angle. Much precaution 
is to be exerted with these. Cut the raw plate with a steel saw 
4mm. thick, 15 mm. square. Make a plane cut as usually 19 
