12<l NEW YORK STATM MITSKtiM 



Thoracoceras wilsoni up, nor. PI. 8, lig. 1-5. Tlie discovery of 

 the si>ooii« herewith presenteil is of more than orclinary interest, 

 not alone from tlie fact that it constitutes a new element in this 

 faiMKi. Imt also because of its very close relation^liip to 

 a form described by Whit(»aves froni the zone with 

 S t r i n g o c e p li a 1 u s b u r t i ii i in the Devonic rocks of 

 Manitoba.^ The associates of this fossil in its occurrence at 

 lakes Manitoba and Winnepegosis as reported by Dr Whit- 

 eaves are, besides Stringocephalus, some forms which pertain 

 to the middle Devonic as develoju'd in New York, such a« 

 C y V { I n a h a lu i 1 t o ii e n s i s, A t r y j) a r e t i c u 1 a r i s and 

 var. a s jM' r a , A c t i n o j) t e r i a b o y d i , P a r a c y c 1 a s 

 e 1 1 i i> t i c a . also P e n t a m e i- u s c o m i s Owen, which is 

 not known to b(^ a New York fossil, but pertains to the upper 

 Devonic horizon in the state of Iowa, and a species identified as 

 K h y n c h o n e 1 1 a p u g n u s Martin, a form already well 

 known from the upi)er Devonic of New York, si>ecially in the 

 Chemung fauna at High point, Naples. So far as the peculiar 

 generic characters of this species of Thoracoceras are con- 

 cerned, they have not heretofore presented themselves in the 

 cephalojKjd faunas of this state. Nor does the association of this 

 species with the fossils of the Agoniatite limestone ju*%tify the 

 construction of the fauna of the latter as in any way indicating 

 the proper geologic horizon of Stringocephalus in the New Y^ork 

 sediments. 



The shell has a slight cyrtoceran curvatun^, notable chiefly in 

 the distal or ajK^rtural region. The cast of the interior shows a 

 very decided prismatic api)earauce, there being 10 well defined 

 prism faces with flat or at times slightly concave surfaces. Of 

 these faces that on the inner cunature of the dorsal surface is the 

 broadest and is well defined over the body chamber, where the 

 other faces become faint or quite extinguished. The body cham- 

 ber shows a slight constriction at about one half its length. In 

 two of the casts in which the body whorl and aperture are 



I DeMjrIptlonM of Bonie new or prevIouBly unknown species of fossils from the Devonian nn-ks 

 of Munltoba. Koyal s..c. Can. TrauH. 18iW. J 4, p. ICJ (lUOlO) pi. -1-10 (7, Ug. 1-4). 



