306 Notice of Ehrenberg’s Memoir on Microscopic Life. 
“The deposit at Andover is . = rich in forms belonging to 
the genus Trachelomonas, and it may consequently be stated that itis 
to a considerable extent formed of loricated monads. 
“ The deposit at New Haven is remarkable for the abundance of. that 
exceedingly minute species, the Staurosira construens, whose numbers 
bear a larger proportion to the mass, than that of the Gallionella dis- 
tans does in the polishing slate of Bilin.” 
Rhode Island.—Lists of marine species from Providence Cove, 
and fossil species from the extensive fluviatile deposit discovered 
by Owen Mason, Esq. in 1838, are given by Ehrenberg, but th 
include only three new forms. 
Massachusetts.—Ehrenberg states that the knowledge of the 
microscopic organisms of Massachusetts has been greatly extend- 
ed by Prof. Hitchcock, who discovered many deposits of these 
fossils during his geological survey of that state in the year 1838. 
Specimens from Andover, Boston, Bridgewater, Pelham, Spencer, 
and Wrentham, received from Profs. Hitchcock, Silliman, and 
Bailey, have been examined by Ehrenberg, who gives long lists 
spe sies noticed from each locality, with sremmarke upon 
n which we select the following. 
«Prom Spencer, in Massachusetts, I received through Prof. Hitch 
ork large pieces of a very white siliceous marl (Kieselguhr) having 
the coherence and color of chalk, but much less dense. I am in doubt 
whether this color is natural or produced by ignition. * * * I might 
conclude that it resulted from ignition, as this matter has been submitted 
to chemical analysis by Prof. Hitchcock, but on the other hand it may 
have been analyzed precisely on account of its whiteness and purity.” 
The species included in the list for this locality, are all fluvia 
tile except the Polythalamian Rotalia globulosa, which being 4 
decidedly marine species, Ehrenberg concludes that the deposit 
must either be situated near a chalk formation, or else near the 
sea. We have already stated (in this Journal, Vol. xii, p. 394) 
our belief that some chalk must accidentally have been ming 
with Ehrenberg’s specimens, as neither the, geological nor ge 
graphical situation of Spencer is such as Ehrenberg suggests: 
Neither can we detect any Rotalia in our specimens. 
Ehrenberg mentions three kinds of iron ochre, sent by Prof. 
Hitchcock from Newbury, Bradford, and Marlborough, ‘but he 
was unable to detect in them Gallionella JSerruginea, oF any 
other organic forms. If they ever existed in these speci | 
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