NIAGARA FALLS AND VICINITY 225 



margin obliquely inward to the eyes, and thence almost directly for- 

 ward, cutting the margin separately. Thorax with nine or 10 seg- 

 ments and grooved and falcate pleurae. Pygidium large and flat, 

 the segments commonly ending in spinous prolongations. Doub- 

 lure very broad. 



Lichas boltoni (Bigsby) (Plate 17) (Hall. 1852. Pal. N. Y. 

 .2:311, pi. 69, 70) 



Distinguishing characters. Large size; nasute anterior end; 

 large central and oblique lateral lobes of glabella; scabrous surface 

 with backward directed acute pustules; strongly striated doublure; 

 three broad lateral lobes of pygidium, contracting to angular ter- 

 minations. 



Found in the lower Rochester shale at Niagara. ! Rare and in 

 fragments. Common at Lockport and elsewhere (Hall). 



Genus encrinurus Emmrich 



[Ety. : encrinus; obpd =tail (from the resemblance of the py- 

 gidium to a crinoid stem)] 



(1845. Neues Jahrb. p. 42) 



Cephaion narrow, wider than long, tuberculated; glabella, pyri- 

 form, prominent; free cheeks narrow, separated in front; eyes small, 

 elevated, on conic prominences. Thoracic segments 11. Pygidium 

 triangular, with numerous segments. 



(• : '\:> 

 Encrinurus ornatus Hall & Whitfield <" . f- <wv\ r J/. / 



(Fig. 157). Cybele punctata / . - \j i-Lij^'V:-- 



Hall (1852. Pal N. Y. 2:297, pi. A66) ' 1 , "j 



Distinguishing characters. Strongly v^;.. / (}. ' '/ 



pustulose surface of cephaion ; pyriform . f 



glabella; elongate triangular pygidium, 



. . , Fig. 157 Encrinurus ornatus 



with concavity along the center of the 



axis, tuberculated at intervals; slender curving ridges of pygidial 



limb, tuberculated at intervals. 



Found in the lower Clinton limestone at Niagara. Rare. Also 

 at Lockport (Hall). 



