b5 



Atry. 



Atrypa exigua. (Hall, Fal. N. Y. Vol. 1, 1847, Trenton 



He. 5 group.) Emmons, x^mer. GeoL I, ii, 1855, page 



^-^ ^^"190, plate 10, fig. 6 a, h, c. Valve with a ridge in 



EmAG^ieiTj mo middle; depressed back; shell surface marked 



with fine concentric linos. Trenton formation. II c, 



Atrypa eximia, 8<r Stenoschisma eximium. VIII g. 

 Atrypa extans. See Camarella extans. II c. 

 Atrypa galeata. See Pentamerus galeatus. YL 

 Atrypa alohuUtorr/iis. See Leiorhynchus globulif . VIII g. 

 Atrypa hemispherica. Leptocoelia hemispherica. V a, 



Atrypa hystrix. (Hall, page 271, fig. 124, 2. H. D. Rogei s, 



p a g o 

 829, fig- 

 ure 681. 

 Vlllg. 

 Chem - 



H.J24-. ' ^\ ung for- 



mation. 

 Claypole, Perry Co., Pa., Report 

 F2, preface. VIII c; Hamilton 

 formation. At Selinsgrove, sec- 

 tion 95, bed 4, White's Report 

 G7, p. 359,inlcwer Chcmuug, VIII g. or Portage, VIII f. — in 

 Erie Co. with other genuine Chemung forms in middle and 

 upper layers of E C White's 325' of Chemung (Q4, p. US).— 

 Quite abundant in the Spirifer led over the Thira Oil SS. at 

 the Carroll quaiijes, at EeBoeuf (Q4, p. 240). — With other 

 Chemung forms at Crowley's run bridge, Greene township 

 (Q4,p.283).— F/77,7. 



Atrypa imbricata {Terehratula imoricata). Hall, Re- 

 port on the Geology of the Eourth distjict of New 

 * York, 1843, page 103, plate fig. [14, l.j Niagara 

 formation. The figure is tak<^n from H. D. Rogers, 

 Geol. Pa., 1858. VI, 



Atrypa impressa. Spec. 854-15 (doubtful species; poor 

 cast, but showing muscular im.jression) ; in Sherwood's coll. in 

 Charleston t., Tioga Co., Chemung upper ^ VIII g. 



K.6U- 



