299 



III J?. 



nisenus arcturus. (Hall, Pal. N. Y. Vol. 1, 1847. Chazy 

 ew.,^M^v"i3 and Black River groups.) Emmons, Am. Geol. 

 I, ii, 1855, page 235, plate 3, fig. 12 ; distin- 

 guished by width of head lobe, at junction with 

 throat (thorax), by the side extent of check- 

 pieces, and by more distinct development of head lobes. Up- 

 per part of Caloiferous sandstone formation. II a. 



lUsenus armatus. Hall, in CoUett's Indiana Report of 

 1881, page 335, plate 34, figs. 10, and 20; and plate 33, fig. 12. 

 See Appendix for -figure, 



Illcenus harriensis. See lUaenus ioxus. V a^ h. 



Illsenus ioxus. {Bumastis harriensis^) Hall, plate fig. [11, 



2] natural size. 

 Hall, 1843, 

 page 101, fig. 

 33,4, of a speci- 

 men nearly 

 twice as large 

 as those com- 

 monly seen,but 

 not as large as 

 the largest 

 which have been found. Niag- 

 ara formation, VI (See Mur- 

 chison's Silurian Researches? 

 page 656, plate 7 bis, figs. 3 a> 

 b, c, d; plate 14, figs. 7 a, 

 b.) Also Hall, plate 19 (11?) 

 1843, fig. 2, (with Lie has 

 {Platynotus) boltoni, and 

 Proetus (Asaphus) cory- 

 phaeus. — In Pennsylvania, it has been found by 0. E. Hall, m 

 the Clinton outcrops of Ferguson Valley, Huntingdon Co. 

 (Proc. A. P. S. Phila. Jan. 5, 1876) ; and by J. J. Stevenson in 

 shale partings of fossil ore hed at Wolfsburg, Bedford Co., Pa. 

 (T2, 144.) — Va. — Note. An Illcenus is shown on specimen 

 506-32, of 0. E. HalPs collections 2 miles south of Bell's Mills, 

 in Clinton red shale. Va, — For other figures^ taken from Hall, 

 in Collett's Indiana Report of 1881, page 835, plate 33, f. 13,14, 

 see Appendix, 



