MARYLAND GEOLOGICAL SURVEY 77 



Charles county, corroborates Leidy's opinion that these are only the 

 worn anterior teeth of the species under consideration. 



Occurrence. — St. Mary's Formation, St. Mary's Eiver. Calvert 

 Formation. Charles county near the Patuxent river. 



Collections. — Philadelphia Academy of Xatural Sciences, Maryland 

 Geological Survey, Museum of Comparative Zoology. 



Suborder ASTEROSPONDYLI Haase. 

 Family NOTIDANIDAE Bonaparte. 



Genus NOTIDANUS Muller and Henle. 

 Eemains of this genus are uncommon in the American Tertiary 

 formations. A single specimen assigned to N. primigenius is recorded 

 by Gibbes from the Eocene ( ?) of Eichmond, Virginia, and the same 

 form is mentioned by Cope as occurring in the Miocene of New Jersey, 

 Maryland and North Carolina. According to A. S. Woodward, the 

 stout, awl-shaped teeth from the " marls of New Jersey," described by 

 Leidy ^ under the name of XipMdolamia ensis, are referable to the sym- 

 physis of the upper jaw of Notidanus. The same author also remarks 

 the evolution of the mnlticuspidate teeth in this genus is analogous to 

 that observed in the grinders of the elephant, there being in both cases 

 a multiplication of similar parts when they occur in series." 



Notidanus primigenius Agassiz. 

 Plate XXIX, Figs. 6a, 6b. 



Notidanus primigenius Agassiz, 1843, Poiss. Foss., voL iii, p. 318, pL xxvii, figs. 



6-8, 13-17 (? figs. 4, 5). 

 Notidanus primigenius Gibbes, 1849, Jour. Acad. Nat. Sci. Pliila., 2nd ser., vol. i, 



p. 195, pi. XXV, fig. 9.5. 

 Notidamts primigenius Wyman, 1850, Amer. Jour. Sci., ser. ii, vol. x, p. 234. 

 Notidanus plectrodon Cope, 1867, Proc. Acad. Nat. Sci. Phila., vol. xix, p. 141. 

 Notidanus primigenius Woodward, 1886, Geol. Mag. [3], vol. iii, pp. 20.5, 253, 525. 

 Heptranchias primigeniiis Hay, 1902, Bull. 179, U. S. Geol. Survey, p. 300. 



Description. — Principal cone of lower lateral teeth relatively large, 

 with prominent anterior serrations on its basal half diminishing in size 



1 Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. viii (1877), p. 252, pi. xxxiv., figs. 

 25-30. 



2 Nat. Sci., vol. i (1892), p. 674. 



