64 LL. Lesquereux on the Coal Formations of N. America. 
I shall not attempt in any way either an exposition or a criti- 
cal examination of the views of the celebrated English author. 
This task has already been admirably fulfilled in a former 
number of this Journal.* Is merely expose the facts that 
appear surely ascertained by a long and careful exploration of 
the coal-fields of North America, leaving the naturalist-philoso- 
just to him. It is a mite only. But the monuments of hu- 
manity, like the mountains of limestone, are built by the slow 
accumulation of minute remains. 
The botanical paleontology of the coal-period and the succes- 
sion and variation of species in the different strata of the coal- 
cannot be studied with more advantage and with more 
measures, 
chances of reliability than in the coal-fields of the United States. 
always detached from the stem. It evidently differs from the — 
genus Cyclopteris by its simple straight nervation and by its up 
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