Orthis. 



518 



of 18, 19; 22, dorsal interior; 23, 

 Aentral interior, scars, teeth, 

 slightly distorted and imperfect; 

 24, 25, dorsal and lateral of small 

 round specimen, strong growth lines, twice natural size. — Hall, 

 Geol. 4th Dist. 1843, p. 105, f. 36, 1 a,7i,7 c. (See March. 

 Sil. Res. 13, f. 11.) In Niagara limestone, Vh 000, p. 233, 

 specimens 506-10, -14, -16, -17, -19, in 0. E. Hall's coll. 2 m. 

 S. W of Bell's Mills, Blair Co., Pa., from Clinton shale, V a. 

 Orthis imperator, Billings. Can. Nat. & Geol. Vol. 4, 



V'"'5^'i 



GeoV^ CancLcLcL 

 1859. Geology of Canada, 1863, p. 129, fig. 55 cj^, dorsal valve • 

 J, side ; c, ventral valve. Ghazy formation, II J. 



Orthis impressa, Hall, Geol. Fourth Dist. 1843, p. 267, 



•ii^flHiHiiimmiiiiH ^ Chemung 



f r ma- 

 tion. — Er- 

 ror on p. 

 54 above. 

 Two fig- 



Va/nu^^'"'*'*™*^"^^^^^ 49- this spe- 

 cies'^from Vanuxem, Geol. Third Dist. 1842, 

 f. 49, have been placed by mistake on page 

 54 of this Dictionary to represent his At- 

 rypa chemungensis. — Also, on page 55 above, Sherwood's spe- 

 cimen 854-15 from Tioga Co., Pa. is wrongly named Atrypa 

 impressa; it should be Orthis impressa. (R. P. Whitfield, 

 MS. correction, 1889.) See 000, p. 145, spec. 12195, Bradford 

 Co. west of Leroy. — It occurs in Carll's collections, 1875, in N. 

 W. Pa. Upper Chemung heds. C. E. Hall, MS. Rt. Dec. 30, 

 1876. — In Columbia Co. in Upper Chemung bed 30 of Sect. 13 



HJ^l. 



