VI. THR TRILOBITES OF THE CHAZN' LIMESTONE. 

 Bv l^ERCv E. Raymond. 



During the forty years which have elapsed since the distinguished 

 Canadian paleontologist, Elkanah Billings, published his descriptions 

 of Chazy fossils, almost nothing has been added to our knowledge 

 of the fauna of the series of limestones which, in theChamplain region, 

 immediately underlie the Lowville member of the Trenton Lime- 

 stone. Billings, in the Canadian Naturalist and Geologist (1859), 

 Decade Four of the Canadian Geological Survey (1859), and the First 

 Volume of the Paleozoic Fossils of Canada (1865), added considera- 

 bly to the very meager list of forms which Professor James Hall had 

 described from the Chazy in the First \'olume of the New Vork State 

 Paleontology. Hall recognized seven species of trilobites, Ilhenus 

 arctuj-iis Hall, Ilhvnus crassicaitda ^ ^^"ahlenberg, Asaphiis obtusus 

 Hall, Asaphus inarginalis Hall, Isotelus caualis Conrad, Isotelus gigas ? 

 DeKay, and Ccrannis sp. undet. Of these, Ilhenus crassicauda ? Iso- 

 telus canalis, Isotelus gigas ? and Ceraunis sp. are so fragmentary as 

 to be unrecognizable, and Illanus ariturus is a s}'nonym for Ilialeops 

 ovata Conrad. The Calyi/ie/ie multicosta ? which Hall described in 

 the same volume from the " Birdseye " of the Isle La Motte is prob- 

 ably the same species that was later described by Billings as AmpJdou 

 canadensis. 



Billings, in 1S65, recognized eighteen species of trilobites in the 

 Chazy fauna, distributed as follows : Asaphus, 2 ; A/nphion, i ; Ani- 

 pyx, I ; Bathyurus, i ; Clieirurus, 3 ; Harpes, i ; Ilhenus, 6 ; Lichas, 

 I ; Reniipleurides, i ; Sp/uerexochus, i ; total 18. 



The species are : 



Asaphus canalis Conrad, Ilhenus vindex Billings, 



Asaphus platycephalus Stokes, Ilhenus chnufrons Billings, 



Amphion canadensis Billings, Ilhenus hayfieldi Billings, 



Ampyx halli Billings, Illa^nus globosus'QWYxw^'s,, 



Ckeinirus safyrus Billings, Ilhenus crassicauda? Hall, 



Cheirurus pompiliui Billings, lichas minganensis Billings, 



Clieirurus prolificus Billings, Bathyurus angclini Billings, 



328 



