370 MESOZOIC FLORAS OF UNITED STATES. 



iron-ore beds of Mr. J. D. Latchford, near Muirkirk, a second from the vicinity of 

 Hyattsville, and a third from simihir claj's next tire shore of the Patapsco River 

 at the Spring Gardens, south of Baltimore." 



The statements that had thus far been pubhcly made relative to the 

 Potomac flora aroused a lively interest among European paleobotanists. 

 There was more or less correspondence with Saporta, Schenk, Nathorst, 

 and Feistmantel, and the last-named author wrote to request further 

 particulars. His letter was referred to Professor Fontaine, who, under 

 date of March 12, 1889, prepared a somewhat full statement of his views 

 relative to the significance of the dicotyledons. A copy of this was sent 

 to Feistmantel, who made it the subject of a paper read before the Roj^al 

 Bohemian Society on April 12, 1889, and published in its proceedings." 



He had already published " a letter on the subject which he wrote 

 to Dr. Ernst Weiss after receiving Professor Fontaine's notes, but in 

 this he does not enter so fully into the discussion. 



Proofs of Professor Fontaine's monograph were corrected in the 

 spring and summer of 1889, and the work, although it bears date 1889,'' 

 did not appear until 1900. 



In this work was laid a solid foundation for the subsequent study of 

 the Potomac formation. In it are described and thoroughly illustrated 

 365 species of fossil plants. If we exclude the dicotyledons, of which 

 only 75 species were found, every class represented greatly exceeds in 

 number of species the same class in the present living flora of the same 

 territorial area. That is to say, there are many more Potomac than 

 present living ferns and conifers, while the large cycadaceous flora of 

 that age is wholly wanting at the same latitudes to-day. But undoubt- 

 edly the most interesting fact is the occurrence at this remote epoch of 

 the first sketches of nature of that great race of plants, the dicotyledons, 

 which now form 75 per cent or more of all vascular plants. 



The work contains three tables of distribution, prepared by myself, 



« Sketch of the history of the Maryland Academy of Sciences, by P. R. Uhler: Trans. Maryland Acad- 

 Sci., Vol. I, Dec. 19, 1888, pp. 1-10. See pp. 7-8. 



'' Ueber die bis jetzt iiltesten dikotyledonen Pflanzen der Potomac-Formation in N. Amerika, mit brief- 

 lichen Mittheilungen von Prof. Wra. M. Fontaine, von Ottokar Feistmantel: Sitzb. d. k. bohm. Ges. d. Wiss., 

 Jahrg, 1889, Vol. I, pp. 2.57-268. 



'■Ueber die bis jetzt geologisch iiltesten Dikotyledonen, von Herrn O. Feistmantel: Zeitsch. d. deutsch. 

 geolog. Ges. Berlin, Vol. XLI, 1889, pp. 27-34. 



''The Potomac or Younger Mesozoic flora, by William Morris Fontaine: Men. U.S. Geol. Survey, V- !. 

 XV, 1889; text, xiv, X 377 pages; atlas, 180 plates. 



