370 MKSOZOIC FLOKAS OF L'MTED STATES. 



iron-ore beds of Mr. .1. D. Latclil'onl, iioar Muirkirk. a socond from tlio vicinity of 

 Ilyaltsvillc, and a tliird from .similar clay.s next, the sliore of tlie Patapseo River 

 at the Spiing Gardens, south of Bahimore." 



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

 Potomac flora aroused a hvely interest ajnong European paleobotanists. 

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

 and Feistmantel. and the last-named author wrote to request ftirther 

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

 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 l)efore the Royal 

 Bohemian Society on April 12, 1889, and pul^lished 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, ai}d the work, although it bears date 1889,'' 

 did not appear until 1900. 



In this work was laid a solid foundation for the stibsequent 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 undoul)t- 

 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, 



a Sketch of the history of the Maryland Academy of Sciences, by P. R. Uhlcr: Tnns. Mnryliind Acad- 

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



'' Ueber die bis jetzt iiltesten dikotyledonen Pflanzen dcr Polomac-Forraation in X. Amcrikn, niit liiicf- 

 lichen Mitthcilunfjen von Prof. Wm. M. Fondiinc. von Ottoknr Feistmantel: Sitzb. d. k. l)ii!im. ties. d. Wi,s.s., 

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



c Ueber die l)is jetzt geologisch iiltesten Dikotyledonen, von Ilerrn O. Feistmantel: Zcitsc-li. d. deutsch. 

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



''The Potomac or Younger Mesozoic flora, by William Morris Fontaine; Mon. I'. S. Cieol. Survey, Vo). 

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



