Maryland Geological Survey 349 



Family GONIOPHOLIDAE 



Genus HYPOSAURUS Owen 



Hyposaurus rogersii Owen 

 Plate VIII, Figs. 3, 4 



Hyposaurus rogersii Owen, 1849, Quart. Jour. Geol. Soc, London, vol. v, p. 



383, pi. xi, figs. 7-10. 

 Holcodus acutidens Gibbes, 1851, Smithsonian Cont. to Knowledge, vol. ii, 



art. v, p. 9, pi. iii, fig. 13 (New Jersey specimen, fide Leidy). 

 Hyposaurus rogersii Leidy, 1865, Smithsonian Cont. to Knowledge, vol. 



xiv, art. vi, pp. 18, 116, pi. iii, figs. 4, 16-21; pi. iv, figs. 1-12. 

 Hyposaurus rogersii Leidy, 1865, Ann. Rept. Smith. Inst, for 1864, p. 68. 

 Hyposaurus rogersii Cope, 1867, Amer. Nat., vol. i, p. 26. 

 Hyposaurus rogersii Cope, 1869, Appendix B, Geol. of New Jersey, 1868, 



p. 736. 

 Hyposaurus rogersii Cope, 1869, Trans. Amer. Philos. Soc., vol. xiv, p. 80, 



pi. iv, figs. 10, 11. 

 Hyposaurus rogersii Cope, 1875, Rept. U. S. Geol. Survey Terr., vol. ii, 



p. 250. 

 f Hyposaurus rogersii Williston, 1894, Kansas Univ. Quart., vol. iii, p. 3, 



pi. i, figs. 4, 5. 

 f Hyposaurus rogersii Williston, 1898, Univ. Geol. Survey, Kansas, vol. iv, 



p. 76, figs. 3, 4. 

 Hyposaurus rogersii Hay, 1902, Bull. U. S. Geol. Survey, No. 179, p. 516. 



Description. — This species, which is the type of the genus, was described 

 by Owen in ]849 and based upon fragmentary vertebrae from the New 

 Jersey Cretaceous. Gibbes in his description of the Mososauroid genus 

 Holcodus, in 1851, included in this species a single tooth from Few 

 Jersey, which Leidy afterward showed was that of a Crocodilian. The 

 latter author also described and figured several teeth from the Matawan 

 formation of Xew Jersey. Similar teeth are not uncommon in Maryland 

 in the Monmouth formation of Cecil County. They are fragmentary and 

 much worn ; conical ; straight sides, except near the base ; longitudinally 

 ridged; about 3.5 cm. to 4 cm. in length and 1.5 cm. in maximum 

 diameter. 



Occurrence. — Monmouth Formation. Bohemia Mills, Cecil County. 



Collection. — Maryland Geological Survey. 

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