174 THE AMERICAN MONTHLY [June, 



Campylodicus. Formerly Campylodicus clypeus was 

 known as a fossil form and occurs in fresh water 

 only. But it is a brackish form in the North sea and 

 there recent. It is rare in the raised coast period of 

 Newark, N. J. 



Dall (1892, Bulletin, U.S. Geol. Survey, No. 34, p. 117) 

 gives an analysis, by Prof. F. W. Clarke, of Bailey's In- 

 fusorial stratum at Ballast Point, Hillsboro County, Fla., 

 as follows : 



Silica 70.78 



Alumina and irou.. . 11.33 



Lime 2.18 



Water and loss 15.71 



100.00 

 Though he says: "An examination of this marl by Mr. 

 Lewis Woolman, the well-known student of microscopic 

 organisms, did not reveal a single diatom," Mr. Wool- 

 man sent me specimens of the marl in which I failed to 

 observe diatoms also. Since then, I got some from Man- 

 itee, Florida, which is south about 35 miles from Tampa, 

 Florida, and for which I am indebted to Mr. K. M. Cun- 

 ningham of Mobile, Ala., and to Dr. D. B. Ward of 

 Poughkeepsie, N. Y., which showed Diatomaceae un- 

 doubtly in fossil condition. The fossil Diatomaceae of a 

 marine condition belonging to the Miocene or Oligocene 

 period have not been detected on the Atlantic side of 

 Fla., in Ga., S. C, N. C. nor in Ala., La., or Tex., nor in 

 Mexico, but we may suppose it possible. That they will 

 be found there, I am sure. I am only waiting for an op- 

 portunity to visit those localities myself, for now I am 

 convinced that the fossil Diatomacea) can only be found 

 by what is called a Diatomaniac, in which category, I am 

 proud to be known. The fossil Diatomacea) of Newark, 

 N. J., were found by myself although travelled over hun- 

 dreds of times by dozens of students and I only found 

 them when my attention was especially fixed upon them 

 and when I had time to look for them. 



