308 Notice of Ehrenberg 's Memoir on Microscopic Life. 



The specimens from Missouri, Mississippi, and New Jersey, sent to me 

 by Prof. Bailey in 1842, for further examination and determination of 

 the forms, have removed all doubts concerning this exceedingly great 

 influence of minute life, which must now be looked upon as a well 

 established scientific fact, and must be attended to in considering the 

 geognostic relations of the earth, and particularly the development of 

 the surface of the earth in all central North America. It would lead 

 too far, to give all the particulars of the rich results lately obtained from 

 these examinations, and as I shall have occasion, in a larger work which 

 is now nearly completed, to present all these details with drawings, 

 comparing all the chalk formations of America, Europe, Asia and Af- 

 rica, I limit myself to this general notice. But be it remarked, that 

 many of the species of European chalk Polythalamia also occur in 

 Asia, Africa, and America,* while some are wholly local. To the lat- 

 ter belong the Textilaria Americana,i whose first and lowest cells are 

 round, while the upper largest cells are always wart-like, longer, and 

 sharper, and at last terminate in a point. This species forms the prin- 

 cipal mass of the chalk of the Upper Missouri. Whether flint, or its 

 equivalent, chalk marl with marine infusoria, occurs there, is still un- 

 known, and is very desirable to determine." 



Part IV, contains an alphabetical list of all the microscopic 

 American infusoria mentioned in this work, with the localities at 

 which each has been found. 



Part V", gives the characteristics of the new genera and species. 



Part VI, includes the general results of the examination, viz. 



1. There is here presented the first general view of the hitherto un- 

 known character of the surface of the earth, for all zones of the whole 

 continent of America. 



2. It proves that not only in situations rich in humus, but also in 

 sandy places of the surface of America, from near the south to near 

 the north pole, there exists an organic life generally invisible to the eye, 

 and that the bottom of the sea is filled with such organic forms. 



* The identity of some of the American Polythalamia with those of England, 

 Africa, and Asia, was made known by us in this Jour- 

 nal, Vol. xli, p. 400, and in the Proceedings of the 

 American Association of Geologists and Naturalists, Vol. 

 I, pp. 356-7. 



t Ehrenberg gives no figure of this species, but it un- 

 doubtedly is the same as that represented in outline in 

 the annexed cut, which we have drawn from the spe- 

 cies most abundant in our specimens of the Missouri 

 chalk marl. Outlines of some of the other forms will 

 be found in this Journal, Vol. xli, p. 400. 



