of Emmons ; in Washington County, JV. Y. 193 



Formation and localities.— Cambrian. Limestones, interbedded 

 in the shaly Taconic slate ; north part of Easton, about one 

 mile south of the village of Greenwich ; on the west side of D. W. 

 Reid's farm and on the summit of the hill, northwest of his 

 farmhouse, about one and one-half miles west of North Green- 

 wich ; about three miles northeast and one and one-half miles 

 east of North Greenwich ; near Rock Hill school-house (No. 8), 

 east of North Greenwich ; and one mile S.S.E. of Battenville, 

 in the town of Jackson, Washington County, N. Y. 



Aristozoe Troyensis Ford. 



Plate I, fig. 8. 



Leperditia Troyensis Ford, 1873. This Journal, III, vol. vi, p. 138; Walcott, 

 1886, Bull. 30, U. S. Geol. Survey, p. 146. 



The discovery of another specimen of this species enables 

 me to refer it to the genus Aristozoe of Barrande. The thin 

 test, grooved and reflected ventral margin, anterior tubercle 

 and general form, all serve to connect it with that genus. In 

 Bull. 30, U. S. Geol. Survey, a figure is given of the right 

 valve, and I am now able to figure the left valve. The tuber- 

 cle on the anterior end is elevated and directed forward. 



Formation and localities.— Cambrian. Limestones, interbedded 

 in the shaly Taconic slates, on the ridge east of the city of Troy, 

 N. Y. ; also at the lowest fossiliferous horizon, on the west side 

 of D. W. Reid's farm, about one and one-half miles west of 

 North Greenwich, Washington County, N. Y. 



Aristozoe rottjndata, n. sp. 



Plate I, fig. 9. 



General outline of the valves subrotund, with the exception 

 of the nearly straight hinge line; anterior end slightly nar- 

 rower than the posterior; general surface rather strongly con- 

 vex, marked all around, except along the hinge line, by a 

 strong marginal groove within a rounded marginal rim ; a 

 single elongate protuberance extends from the main body of 

 the shell upward, just within the anterior marginal groove and 

 the hinge line, where it is most prominent, and separated from 

 the main body of the valve by a broad sulcus extending from 

 the hinge line down on the valve over two-fifths the distance 

 to the ventral margin. 



The shell is thin and apparently very finely granulose. 



A comparison with the types of the genus Aristozoe shows 

 this species to be congeneric with them and specificially dis- 

 tinct from any described species of the genus. Aristozoe 



Am. Jour. Sci.— Third Series, Vol. XXXIV, No. 201.— Sept., 1887. 

 13 



