404 Forty-second Report on the State Museum. 



species, described in Volume VII of the Palaeontology of New York as 

 Bronteus tullius, Hall (pp. 12, 13, pi. viiia, figs. 34-36), is characterized 

 by its broad, flattened pygidial annulations, which become obsolete 

 only near the margin, the median rib being simple, not bifurcated as 

 in many species occurring in the Upper Silurian and lowest Devonian 

 faunas, and also by the presence of a row of minute spinules about the 

 postero-lateral margin, which demonstrate the relations of the species 

 to the characteristic Devonian subgenus Thysanopeltis. In the Chemung 

 species (which may be designated Bronteus senescens), we are presented 

 with considerably greater dimensions, the original width of the pygi- 

 dium being about 40mm. Unfortunately, no portion of the postero-lat- 

 eral margin has been retained, and its relations to Thysanopeltis can not 

 be ascertained. The axis is short and relatively wide. Of the fifteen 

 annulations, the median is quite narrow and appears to be simple, 

 though its lower portion is lost. The lateral annulations vary greatly 

 in size; those adjacent to the median rib are of about the same width, 

 i. e.j very narrow, widening posteriorly, while the next three pairs are 

 broad, somewhat flattened, and widen very slightly as they extend 

 backward. The succeeding three pairs originate in acute apices at the 

 axis, and widen very rapidly, the width of any one of them, at the 

 obsolescence of the sulci, equaling or exceeding that of any two of 

 the others. The sulci are narrow and smooth, soon becoming obsolete 

 and leaving the marginal portion of the shield relatively broad. The 

 rapid obsolescence of the ribs indicates that the pygidium must 

 have been comparatively short, and, if the outline given it in the 

 accompanying figure be approximately correct, it indicates a peculiar 

 form of pygidium, rarely met with in the genus. (Conf. Bronteus 

 Gervillei, Barrande, in Barrois' Faune du Calcaire d'Erbray, 1889, p. 233, 

 pi. 17, fig. 2.) The anterior portion of the annulations is covered 

 with granules varying considerably in size, becoming quite conspicu- 

 ous tubercles on the median and two adjacent ribs. 



This specimen was collected by Mr. D. D. Luther, of Naples, from 

 the lower beds of the Chemung group, in a gully opening into Italy 

 Hollow, Yates county, and extending southward within the northern 

 boundary of the town of Prattsburgh, Steuben county. Attached to 

 the specimen is the impression of a dorsal valve of Productelta speciosa 

 or lachrymosa, and a number of fragments of Fenestella. The horizon 

 at which it occurs can not be far above or below that of the peculiar 

 High Point fauna occurring in the adjoining township of Naples, 

 Ontario county, and discussed by the writer in Bulletin No. 16, U. S. 

 Geological Survey (pp. 72-76, 1885). It was shown in this paper that' 

 the first appearance of a characteristic Chemung fauna in this section, 



