S06 Marsh, description of a new Enaliosaurian 



observed in the coal strata at Greensburg, Penn * In 1852 Sir 

 Charles Lyell and Prof. J. W. Dawson obtained in the Coal- 

 measures of Nova Scotia the bones of the Dendrerpeton Acadia- 

 num (Wyman and Owen), which were the first reptilian osseous 

 remains described from the Carboniferous rocks of America.f 



Since these discoveries were made, the Coal-fields of England 

 and Nova Scotia, as well as those of Ohio and Pennsylvania, have 

 aff'orded additional Batrachian, or Amphibian, bones and foot- 

 prints, so that at the present time the prevalence of this type 

 of reptilian life during the Carboniferous period is generally ad- 

 mitted. The more recent researches of Prof. Dawson in the 

 Coal formation of Nova Scotia have been rewarded by the im- 

 portant discovery of a new genus (^Hylonomus) of very small rep- 

 tiles, which, he considers, had affinities to the Lacertians, and 

 possibly belonged to that family, rather than to the Batrachians.| 



The remains which form the subject of the following description 

 are of great interest, since they indicate the existence during the 

 Palaeozoic period of a group of highly organized marine reptiles 

 of large size, which have previously been found only in Second- 

 ary strata. These remains consist of two vertebrae, or more strictly 

 two centra or bodies of vertebrae. The vertebrae was discovered 

 by the writer in August, 1855, while examining the Coal-measures 

 of Nova Scotia in company with his friend, Mr. WiUiam E. Park, of 

 Andover, Mass. Their resemblance in form and appearance to the 

 vertebrae of an Ichthyosaurus was so marked, that at the time of the 

 discovery the writer referred them to that genus, and made a careful 

 exploration in the vicinity for further remains, but without success. 

 As soon as an opportunity occurred, the fossils were compared 

 with the vertebrae of Ichthyosauri from the Lias, and, although 

 some points of difi'erence were noticed, the Enaliosaurian charac- 

 ters seemed to be equally well marked in each. Wishing to ob- 

 tain, if possible, some additional remains, the writer for sometime 

 deferred publishing a description of the vertebrae ; but a careful re- 



* Description of fossil footmarks (of Thenaropus heterodactylum) found 

 in the Carboniferous series in Westmoreland County, Penn. ; by Alfred 

 T. King, M.D., Am. Journal of Science, vol. xlviii, page 343. Also in 

 vol. i, new series, page 268. 



f On the remains of a reptile (Dendrerpeton Acadianum, "Wyman and 

 Owen), and of a land shell discovered in the interior of an erect fossil 

 tree in the Coal-measures of Nova Scotia ; by Sir Charles Lyell, F.R.S., 

 &c., and J. W. Dawson, Esq. Quarterly Journal of the Geological So- 

 ciety, London, May, 1853, vol. ix, p. 58. 



X Proceedings of the Geological Soc. of London, 1859. Also Supple- 

 ment to Acadian Geology, page 33. 



