340 Prof. Bailey on Fossil and Recent Infusoria. 



were Pinnularia incBqualis, Cocconema cymhiforme, Gallionella 

 distans, Himaiitidiwm Areas, Stauroneis Baileyi, Surirella 

 splendida, Spongiolites lacustris, Closterium crenulatum ! stel- 

 late hairs of Platanus 1 pollen of Pine, and seed-vessels of Ni- 

 tella or Char a. 



If, as I have no reason to doubt, the n:)arl examined was really 

 that in which the bones were imbedded, these results are inter- 

 esting as they prove, 1st. That siliceous infusoria identical with 

 those now living were cotemporaneous with the mastodon. 2d. 

 That not only siliceous but 'membranaceous infusoria, hairs of 

 plants, &c. may be preserved for ages in calcareous marls, where 

 they may be detected after the calcareous matter is dissolved by 

 acids. 



In connection with this I may state, that this same method of 

 observation was applied by me two years ago to specimens of 

 calcareous marls from New Hampshire, sent by Prof. Hubbard, 

 and marls from New York, sent by Prof. James Hall, and that I 

 detected in them not only siliceous infusoria, but a number of 

 well preserved membranaceous coverings of animalcules, such as 

 various species of Closterium, Euastrum, &c. I believe that the 

 occurrence of these in a fossil state has not previously been no- 

 ticed. 



IX. Fossil Polythalamia of the United States. — I take this 

 opportunity to tender my thanks to numerous persons who have 

 kindly sent me specimens of \^arious secondary and tertiary marls; 

 and although 1 have myself, from the want of time and books, 

 stirunk from the task of determining and describing the nu- 

 merous species of American fossil Polythalamia which I have 

 thus been enabled to prove to exist at so many localities ; yet 

 no one can regret this, as I have been fortunate enough to in- 

 duce Ehrenberg to undertake this labor. I have lately had the 

 pleasure of learning from him that he has received all the speci- 

 mens which I have forwarded to him, and that he is actively 

 engaged in studying them. While we wait therefore for the 

 results of Ehrenberg's examination, it may still be of some in- 

 terest to present a list of all the North American localities at which 

 I have proved Polythalamia to exist. They are enumerated in 

 the following table. 



