PREKACE. 



THE Diatoms have perhaps been more thoroughly studied 

 than the other Algee, especially within the past fifty years. 

 Among the noted investigators of American Diatoms was Dr. 

 G. C. Ehrenberg, of Berlin, Germany, who in his several visits 

 to this country, made careful explorations all the way from the 

 Atlantic to the Pacific coast. His labors resulted in his cele- 

 brated work on Microgeologle or Microscopic Organisms < Diato- 

 niacea?) published 1854-5J, besides numerous short papers in the 

 Journals of the Academy of the Natural Science of Berlin. Pre- 

 vious to Ehrenberg's publications, Prof. J. 1ST. Bailey, of West 

 Point, N. Y., turned his attention to the Diatoms of the United 

 States, and frequently contributed papers on this subject to the 

 American Journal of Sciences and Arts (Siliman's Journal), 

 New Haven. In 1S50 the Smithsonian Institute published 

 his Microscopical observations in South Carolina, Georgia and 

 Florida. Somewhat later, A. M. Edwards published several 

 papers on the United States Diatomace;e ; and F. W. Lewis, 

 M.D., contributed between 1861-05, notes on "New and Barer 

 Species of Diatoms of the United States Sea Board ;" "On New 

 and Singular Forms," etc. From this time contributions to the 

 literature of Diatoms became more numerous. One of the most 

 valuable of them, appeared in The Leu*, Chicago, 1S7L', by Prof. 

 H. L. Smith, entitled "A Conspectus of the Families and Genera 

 of the Diatomacese." Among other prominent investigators are 

 Prof. J. D. Cox, of the Law School of Cincinnati; Dr. H. H. 

 Chase, of Geneva, N. Y., and later of Michigan ; C. S. Peticolas. 

 of Bichmond, Va., an industrious collector of the fossil Diatoms 

 in his vicinity; Messrs. Briggs and Thomas, of Chicago, whose 

 names are associated with the local Diatomace;e ; Kain, of Phila- 

 delphia, Pa., familiar with the forms about Atlantic City, N. J.; 

 Shultze, whose field is Staten Island and the neighborhood of 

 New York City; Vorce, of Cleveland. Ohio; Newcomber. of 

 Indianapolis, Ind. : M. A. Booth, Longmcado\\ . Mass.. and 



