Mineralogy and Geology. 435° 
Fucoids—The F. simplex is undoubtedly a -graptolite, and is appa- 
rently identical with a species in the unaltered slates of the Hudson 
_Tiver group. The F. rigida (which is the same as F. flexuosa) is be- 
yond doubt a Hudson river species. 
Becraft’s mountain, east of Hudson, 3 miles from the Hudson river, 
; 
slates? The facts show plainly that the slates below, are no other than 
the Hudson river slates, as I have before ed 
8. Dolomisation.—M. Delanotie denies that dolomisation is a result 
nying the alteration of rocks: and takes the ground that crys- 
9. Mikrogeologie: Das Erden und Felsen schaffende Wirken des 
’ unsichtbar kleinen selbstandigen Lebens auf der Erde, von C. G. Euren- 
BERG. 1 vol. folio, with 41 plates. Leipsic, 1854. Price $72.—A large 
Portion of the text, with 41 folio plates of this magnificent and long ex- 
pected volume is now published, giving the results of fourteen years of 
zealous and unwearied labor on the part of the distinguished author in 
Waters, as well as the solid strata of the earth. e author states in 
the introduction, p. ix, that his great work, “ Die Infusionthierschen,” pub- 
lished in 1838, is to be considered as an introduction to the present vol- 
umefand we notice in various parts of the present work that not on 
of the much controverted positions assumed in the former work has been 
- The term Polygastrica is retained; implying of course that the 
