212 NEW YORK STATE MUSEUM 



aperture and the surface marked by fiue lines of growth and 

 longitudinal lines, strengthened at regular intervals. 



The nautiloids are represented by Nautilus (D i s c i t e s) 

 m a r c e 1 1 e n s i s [fig. 156], characterized by an angularity 

 of the umbilical margin of the whorl, by a noded outer or ventro- 

 lateral margin, and by a suture having a broad lateral lobe, with 

 angular saddles on the umbilical and ventrolateral margins, and 

 a rounded lobe on the venter. 



The goniatites of this limestone are represented by the large 

 and characteristic Agoniatites expansus (Vanuxem) 

 [fig. 157] (Goniatites vanuxemi Hall). This species 

 when adult is a foot or more in greatest diameter, with a large 

 living chamber, which has flattened sides and a rounded venter. 

 In the earlier stages of development the venter is flattened and 

 margined by ventrolateral ridges. The surface is furthermore 

 ornamented by sinuous ridges. The suture is simple, with a 

 narrow ventral or siplional lobe. Parodiceras dis- 

 co id eum [fig. 158] is a smaller smooth species, with the um- 

 bilicus closed, owing to the close coiling of the shell. This char- 

 acter is shown even in the young specimens. - 



Hamilton shales 



The Marcellus shales are succeeded by arenaceous beds, chiefly 

 more or less impure quartz sandstones alternating with silicious 

 clay mudrocks which often become shale. In the coarser sand- 

 stones, brachiopods not infrequently occur, chiefly as molds, 

 S p i r i f e r g r a n u 1 o s u s predominal ing. The lower beds 

 of this series are shown in the cliff of Vroman's Nose, which rises 

 some GOO feet above the level of the Schoharie river. The lower 

 beds here are (lark gray shales and thin sandstones, the former 

 becoming more blocky toward the top. In the coarser beds, 

 S.pirifer g r a n u 1 o s u s is common together with the 

 curious marking know n as Spirophyton and already represented 

 in the Ksopus shales. 



Another cliff of Lower Hamilton strata is seen in the south- 

 western portion of J lart man's hill, 1 east of Middle-burg. These 



*So named from one of the early settlements of the Palatines at the foot 

 of this hill, which was called Hartman's Dorf. 



