306 Notice, of Ehrenberg'' s Memoir on Microscopic Life. 



" The deposit at Andover is extremely rich in forms belonging to 

 the genus Trachelomonas, and it may consequently be stated that it is 

 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 they 

 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 

 of the species noticed from each locality, with remarks upon 

 each, from which we select the following. 



" From Spencer, in Massachusetts, I received through Prof. Hitch- 

 cock 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 iluvia- 

 tile except the Polythalamian Rotalia globulosa, which being a 

 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. xliii, p. 394) 

 our belief that some chalk must accidentally have been mingled 

 with Ehrenberg's specimens, as neither the geological nor geo- 

 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 ferrnginea, or any 

 other organic forms. If they ever existed in these specimens, 



