734 



Report of the State Geologist. 



Soon after the publication of, the article above cited, the writer located 

 the horizon at which this fossil occurs, on Bardeen's farm in the northern 

 part of the town of Prattsburgh, finding here several nearly entire pygidia. 

 This horizon is well characterized by the constant association of this trilobite 

 with the crinoid Arthracantha depressa ; a species recently described by 

 Wachsmuth and Springer from specimens collected at this locality where its 

 spinous plates are very common. It is the zone of Rh g/ichonella (Pngnax) 

 pugnus, Sow., and is an eastward extension of this zone from its somewhat 

 more prolific manifestation at High Point, in the town of Naples. More 

 recently two essentially entire specimens of the trilobite have been obtained 

 from higher strata of the Chemung group, near Avoca, Steuben county, 

 through the agency of Mr. Clifton J. Sarle, both excellently preserved though 

 lacking a few details, but presenting us with a really striking exempli- 

 fication of the late continuance of this genus. 



Figures of these specimens are here given and the description of the 

 characters of the species is as follows : 



Figures 3 and 4. Bronteus senescens ; two nearly entire individuals from the Chemung group, 



near Avoca, N. Y. 



General Proportions. The outline of both of these extended 

 individuals is quite regularly ovo-elliptical, the shorter curve being at the 

 ] ii isterior extremity. In length the larger measures 54 mm., the smaller, 46 

 mm., while the greatest width of the animal is about one-half this dimension 

 in both cades. The specimens have been subjected to slight, if any, vertical 

 compression though the heads are somewhat askew; the lines of the margin 

 may, therefore, be regarded as normal. 



