Clarke — Crustaceans from the Chemung Group. 



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and clean-edged throughout their extent ; and again by the presence of similar 

 but straighter and more slender spines upon the final segment of the abdomen. 

 Of the latter, two pairs are visible, the penultimate pairs appearing to be 

 somewhat longer than the ultimate ; there are traces also of a similar pair on 

 the antepenultimate segment. 



This description presents all the known characters of this peculiar 

 crustacean. Its essential structure is nearest to EeliinocariH and yet not in 

 harmony with that genus, and its extravagant decoration emphasizes that 

 generic difference. For this reason the generic term Peplvrica/ris is adopted 

 for the fossil, and the species may be known as Peph ricari* horripilata. 



Both specimens of the species were found in loose blocks of compact 

 Chemung sandstone at Alfred, N. Y. Neither shows associated fossils. 



IL The Chemung Trilobite, Bronteus senescens, Clarke. 



In the Report of the New York State Geologist for 1888, the writer 

 described the trilobite above named.* The single specimen upon which the 

 description then published was based, was but a very imperfect fragment <>f 

 a pygidium and the only justification for drawing attention to the fossil was 

 the extreme rarity of all trilobites in the Chemung faunas. At the date of 

 that writing the presence in the Chemung of the species Phacops rana, (rreen, 

 common in the Hamilton rocks beneath, and not of infrequent occurrence in 

 the Ithaca fauna immediately below the Chemung formation, was suspected, 

 and had been announced. Later evidence has not confirmed this statement, 

 and we know to-day only two described species of trilobites from this fauna; 

 the Cyphaspis lewis, Hall (sp.), the original and only known specimen being 

 a cephalon, and Bronteus senescens. The presence of the genus HomalcmolfiLS 

 is shown by a fragment from the higher beds in Alleghany county. Since 

 the description of Bronteus senescens, founded mi a specimen from the lower 

 Chemung strata in the town of Prattsburgh, Steuben count)-, additional 

 material has been obtained which sets forth the characters of the species in its 

 entirety and also shows that from the fragment previously figured and the 

 restored outline at that time given to the pygidium, it might prove difficult to 

 recognize the species when at its best. A restatement of the characters of the 

 fossil drawn from our amplified know ledge of it, will therefore serve to clearly 

 define the value of this species. 



* The Genus Bronteus in the Chemun« Rocks of New York, op. tit.. Figure 1 ; also published in Forty -second Annual Report 

 Trustees Stale Museum, pp 403 405. 



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