MARYLAND GEOLOGICAL SURVEY 229 



U. affinis Lesq. (Mem. Mtis. Comp. Zool. Harvard College, vol. vi, No. 

 2, p. 1G, pi. iv, figs, 4, 5) which, however, is described as long petioled; 

 U. pseudo-americana Lesq. (Cret. and Tert. Fl., p. 249, pi. liv. 

 fig. 10) which differs principally in its larger size and in the strict, paral- 

 lel character of its nervation; U. tenuinervis Lesq. (Ann. Eept. XJ. S. 

 Geol. and Geog. Snrv. Terr. 1873 [1874] p. 412; Tert. FL, p. 188, pi. 

 xxvi, figs. 1-3) which is more elongated; and also with U. fislieri Heer, 

 U. plurinervia Ung. and U. bronnii Ung., all of which species differ from 

 each other no more than the leaves of U. racemosa or U. americana on 

 a single branch often differ between themselves. The apparent relation- 

 ship is indicated in the specific name adopted, instead of referring the 

 fossil, without question to the living species. 



Occurrence. — Sunderland Formation. Near the headwaters of Is- 

 land Creek, Calvert County. 



Collections. — Maryland Geological Survey. 



Ulmus sp. ? 

 Plate LXIX, Fig. 10. 

 Description. — This fragment is too imperfect for more than generic 

 determination, but apparently it belongs to the living U. racemosa 

 Thomas. 



Occurrence. — Talbot Formation. Grove Point, Cecil County. 

 Collections. — Maryland Geological Survey. 



Genus PLANERA J. F. Gmel. 

 Planera ungeri Etts. 

 Plate LXXI, Figs. 14, 15. 

 Planera ungeri Etts, 1851, Foss. Fl. Wein, p. 14, pi. ii, figs. 5-18. 

 Description. — This species, as originally depicted by Ettingshausen, is 

 represented by small leaves similar to those now figured, but other au- 

 thorities have included a wide range of forms, varying greatly in size, 

 shape, and character of the dentition. (See Heer, Fl. Tert. Helvet., vol. 

 ii, pi. lxxx; Fl. Foss. Arct, vol. i, pi. ix, fig. 14b; ibid. vol. ii, Fl. Foss. 



