500 General Notes. [June, 
book, and richly illustrated with admirable drawings, without 
whose assistance a description is not intelligible. 
4. From the great rapidity with which, under proper surround- 
ings, the Bacteria and even the fresh-water Desmids grow and 
multiply, the considerable thickness of strata which the siliceous 
cells of the latter accumulate in a few years, there is no longer 
difficulty in the way of understanding the formation of coal beds 
now, nor the absence of microscopic structure in all true coals, 
nor their compactness. For pressure alone is amply sufficient 
to produce this density. Nor is the difference in chemical compo- 
sition of various coals now so much astonishing, since this will 
depend on the composition of the predominating protophytes of 
the stratum. However, these points are not investigated yet, as 
indeed the whole study has not advanced beyond the establish- 
ment of a few fundamental theses. Professor Reinsch does not 
expect a rapid acceptation of his views, but he desires stimulating 
capable observers everywhere, to carry the light of science into 
this dark field of hereditary beliefs. ; 
In conclusion, we would heartily congratulate Prof. Reinsch 
for this invigorating contribution to geology, in the prosecution 
of which upon our vast carboniferous areas, botanists and chemt- 
Bulletin, No. 32. 
Empedias (= Empedocles nom, praeocc.) and Dimetrodon. 
GEOGRAPHY AND TRAVELS! 
Important Discovertes in Sourn America.—In the Natu- 
de Dios rivers, in Brazil. He proposed to continue the wor : 
the late Professor Orton, so sadly interrupted by his death. T . 
Kansas City Review of Science for April, contains an interesting 
. wake 
account of the success of Dr. Heath’s expedition. He has 
* Edited by Ettts H. YARNALL, Philadelphia, 
