M.\i;vi,.\.\i) ci'Oi.ocic \i, siu\i:v 10;i 



SvM:( IIODIS CLAKKll II. S|). 



rintr Xl\', I'i^s. :.;.. :)l), :.<■. 



nrscrlp/ldn. — Tcctli of >iii;ill oi' iiKnlci-ali' size. Will <i\' I't'latively stout 

 |ir()|i()i't idiis, and syiiiinrl lical. Mc(liaii mwc -liarplv recurved, frcntly 

 ia|>criii,i:-. smooth, coiivcx on Imtli Faces, ami ciiltim^' cdo-eg not coiis|iicii- 

 oiisly (Icliiicd; on eitlier side, two iiiiicli smaller cones, the external one 

 lieiii^ (he lesser of tlie two. l\oot iiia.ssive and somewhat turgid, pro- 

 duced ill the arc of a circle on the inner face, and flat below; nutrient 

 rorameii small. 



'i'lic total height of the tooth, oriented in its natural position, is 7 mm. 

 The distance from apex to base of crown, measured along its recurved 

 outer face, is G mm. The width and thickness of the crown at its base 

 are equal, amounting to 3 mm., whereas the corresponding measure- 

 ments of the root, taken at their maximum, are 8 mm. and 4 mm. re- 

 spectively. 



This unique tooth appears sufficiently -well characterized, notwith- 

 standing that the lateral cones are broken off above the base, to warrant 

 recognition as a distinct species, and it may be fittingly named in honor 

 of the State Geologist. Much interest is attached to the fact of its 

 coming from a Tertiary horizon. 



Occurrence. — Aquia Foematiok. Liverpool Point. 



Colleciion. — Maryland Geological Survey. 



Family LAMNIDAE. 



Genus ODONTASPIS Agassiz. 



The teeth of this genus are very similar to those of the Cretaceous 

 Scapanorliynclius, a survivor of which has been recognized in 2Lits\l'u- 

 rina of the present day; and they are also, as remarked by Agassiz, very 

 difficult to distinguish from those of Lamna. The crown is high, nar- 

 row and compressed in all except a few hindermost teeth, and adjacent 

 to it are one or two pairs of lateral denticles, generally sharply pointed. 

 The anterior teeth are especially high-crowned, comparatively large and 

 slender, with a much produced l^ifurcated root. 



