Ohio, Germany. 
Nematophyton from Canada. 
Carbonized impressions = Mazon Creek (Illinois), 
Pennsylvania, Holland, England, France, 
Germany, Switzerland. 
Bituminous coal = Pennsylvania, Ohio, Antarctic. 
Anthracite coals = Pennsylvania. 
Peeling the Carbonization. This procedure is 
based upon the schedules used for four types of speci- 
mens: a Carboniferous calamite cone (Macrostachya 
Thompsonii Darrah) with spores, sporangia, and sporan- 
giophores, all preserved; a Carboniferous fern fructifica- 
tion (Crossotheca sagittata (Lesquereux) Sellards) show- 
ing spores in place; a Triassic cyeadean frond from which 
was obtained cuticles with the stomata preserved; and a 
Miocene leaf with basidiomycete decay spots. Before 
the specimen is etched, it is necessary to lay bare the 
sporangia with a fine chisel and a jeweler’s hammer. 
On a carbonization or incrustation the surface to be 
etched is more or less even. The acid solution (usually 
1% to 5% hydrochloric) is carefully applied and the ex- 
cess removed with water. After the specimen dries, ni- 
trocellulose solution is poured over the surface. If the 
specimen is very uneven, it may be desirable to build up 
the peel by several layers of solution. The dried peel, 
after removal, should be flattened under a weight in a 
warm-chamber of 140° F. for an hour. 
There is scarcely a limit to which this peel method 
may be applied in paleobotany—provided that cellular 
structure is preserved and that the rock can be etched or 
attacked with an acid. Graphitized impressions can be 
removed from slate, but the cell structure has been de- 
stroyed during metamorphism. 
Coal. We have had some success with coal. <Al- 
though improvements must and will be made, it is of 
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