PALEOZOIC TIME — DEVONIAN. 579" 



Beecher and Clarke in the Am. Jour. Sc, 1892 ; of eastern Pennsylvania, by I. C. White 

 in Penn. Geol. Rep., G 6, 1882 ; of Illinois, in the Geol. Rep., 111., by Worthen, vol. iii. ; 

 of Canada, in Can. Geol. Rep., 1863, and also in later Annual Reports. Among the 

 Brachiopods of the Oriskany occur the genera Orthis, Stropheodonia, Leptoena, Rafines- 

 quina, Chonetes, Leptostrophia, Meristella, Cyrtina, Spirifer, Rhynchouella, Centronella, 

 Cryptonella; also the genera Rensselceria, Eatonia, Leptocoelia, which are more largely 

 developed in the Oriskany than in any other period. Orthis hipparionyx = Hipparionyx 

 proximus, Spirifer arenosus, S. arrectus, Leptocoelia flahellites, Cyrtina rostrata, Rens- 

 selceria ovoides are characteristic species. 



The Illinois beds, of cherty limestone, have afforded Anoplia nucleata, Rhynchonella 

 speciosa, Eatonia peculiaris, Leptocoelia flahellites, Newherria Condoni, Amphigenia 

 elongata, Strophostylus ? cancellatus, Platyceras spirale, and other species. At Becrafts 

 Mountain, the species include, according to C. E. Beecher and J. M. Clarke, six species of 

 Dalmanites, two of Phacops, a Homalonotus, Cyphasphis, Proetus, Acidaspis ; a Cirriped 

 of the genus Turrilepas ; corals of the genera Zaphrentis, Romingeria, the Crinoid 

 Edriocrinus sacculus. The unusual number of Trilobites for the Oriskany indicates 

 apparently clearer waters along the Hudson River valley than to the westward along 

 central New York. The Lower Helderberg species obtained are Acidaspis tuberculata of 

 the Shaly limestone, a Cyphaspis, two Dalmanites, and a Phacops of L. H. type ; Tentacu- 

 lites elongatus ; Orthis perelegans, and 0. ohlata? of the Shaly limestone; Leptostrophia 

 Becki, Trematospira multistriata, of the Shaly ; a Coelospira, Anastrophia ; Eatonia 

 medialis, of the Shaly ; a Zaphrentis, Shaly in type. The Devonian forms are 

 Dalmanites phacoptyx (known previously only from the Upper Helderberg of Ontario), 

 a Phacops, Leptostrophia peiplana, a Chonetes ?, Hemitrypa ?, Fenestella celsipora of the 

 Corniferous. At Parlin Pond, in western Maine, there occur Reiisselceria ovoides, Lepto- 

 coelia flahellites, Spirifer arrectus H., S. pyxidatus H., Stropheodonia magnifica H., Rhyn- 

 chonella ohlata H., Orthis musculosa H., Dalmanites pleuropteryx, etc. (Billings). 



See, further, on the relations of the Lower Helderberg, Oriskany, and Devonian faunas, 

 the remarks on page 569. 



2. Corniferous Period. 



The Corniferous period includes two epochs, the Schoharie and the 

 CoENiFEROus, To the former belong the Cauda-galli grit and the Schoharie 

 grit, now considered cotemporaneous formations ; to the latter, the Cor- 

 niferous limestone. 



ROCKS— KINDS AND DISTRIBUTION. 



The rocks of the Corniferous period in New York have their greatest 

 thickness in the region of the Eastern Interior Sea, along the Appalachian belt. 

 The Cauda-galli grit, a dark gritty slate, thickens toward the Hudson, being 50 

 or 60 feet thick in the Helderberg mountains, and 100 to 150 feet east of the 

 Hudson River in Becrafts Mountain, near Hudson ; and the Schoharie grit is 

 best displayed in the eastern counties of New York, Albany, Greene, and 

 Schoharie. Neither formation is found to extend far west over the Oriskany 

 beds of western New York and Ontario. The Cauda-galli, like many seashore 

 deposits, is almost destitute of fossils ; but the Schoharie beds abound in them, 

 and they are closely related to those of the following Corniferous epoch. 



The Corniferous limestone — so called by Eaton, with reference to the 

 ^ornstone or flint often imbedded in it (from the Latin cornu, horn) — extends 



