547 



Orthoc. 



(or species?) having direction of septa and rings coincident. 

 A specimen about | in. thick has 7 or 8 septa to the inch; 

 rings cross so that half the ring is on one chamber and half on 

 the next lower chamber. Hamilton soft shales on Seneca and 

 Cayuga lakes and elsewhere in N. Y. — VIII c. In Pennsyl- 

 vania recognized by Hall in Spec. 808-18 (00, p. 235) Fellow's 

 Coll. at Dingman's falls, Pike Co., Pa., in Hamilton rocks ^ 

 VIII c ; and by Stevenson in the upper Devonian strata in 

 the gaps of Fayette and Westmoreland Cos., Vdi.— VIII-IX. 



Orthoceras demus, Hall. Pal. N. Y. Vol. 5, 1879, page 311, 



Xa P/.XC. 



plate 90, figs. 1, 4, 5; found, associated sometimes with 0, 

 fulgidum, in lime shales at Ithaca and Philipsburgh, N. Y. 

 Chemung,— Q\2CY^o\(d'% specimen 53-26 (000, 12,009) on New 

 Bloomfield road to Carlisle, Perry Co. Pa. Chemung, VIII g. 



Orthoceras deparcum, Billings. Geology of Canada, 1863, 



17/ =^page 121, fig. 40. Calciferous sandstone. 



II a. 



126 



XIII. 



Daw 



Orthoceras dolatum, Dawson. Acadian Geology, 18 — 

 page 311, fig. 126 ; like 0. pygmceum, DeKon. ; flat- 

 tened on one side; siphuncle near flattened side. 

 ^ Carboniferous limestone of Windsor N. S — 



G XIII? 



Orthoceras duseri, H. & W. Pal. Ohio, Vol. 2, 1875, page 

 97, pi. 3, fig. 2, the perfect and type specimen, (fig. cut in half 

 and doubled on itself to get it into this page,) showing all the 

 characters except the outer or last chamber; fig. 3, one septum 

 and a single head of the siphuncle, as seen by breaking the 

 specimen ; fig. 4, magnified view of the peculiar net work tex- 



