Geol.— Vol. I.] SMITH— COMPARATIVE STRATIGRAPHY. 4OI 



Sagenites herbichi \s common in the Upper Trias, Karnic 

 stage, zone of Tro^ites suhhullatus of the Alps. In Cali- 

 fornia it is common in the same horizon, associated with 

 Trofites siibbuUattis, Paratropites sellai, Halobia superba, 

 etc., in Shasta County, on Brock Mountain, on the divide 

 between Squaw Creek and Pitt River, about six miles north- 

 east of the Bully Hill Mine. A similar and probably iden- 

 tical species has been found in the Himalayas in India, so 

 this form may be considered as characteristic of the Karnic 

 stage. 



Genus Proclydonautilus Mojsisovics. 



1902. Proclydonautilus, Mojsisovics, Das Gebirge um Hallstatt, Supple- 

 ment-Heft, p. 207. 



Type, Nautilus griesbachi Mojsisovics. 



Generic characters: Form involute, with high, rounded whorls, nearly 

 smooth shell, narrow umbilicus, and nearly central siphuncle. The septa are 

 divided into several lobes and saddles. The broad ventral saddle is divided 

 by a shallow funnel-shaped lobe; there is also a broad and deep lateral lobe. 

 The internal part of the septa shows no lobes nor saddles. 



The young stages are like the Carboniferous genus Colo- 

 ceras Hyatt (^Naiitiliis globatus Meek & Worthen), and the 

 transition from the Paleozoic to the Triassic type of septa 

 is very gradual. Mojsisovics^ formerly classed Nautilus 

 triadicus under his genus Clydonmitilus, from which, how- 

 ever, it may easily be distinguished by having one less lateral 

 lobe, and a rounded instead of angular whorl, and by the 

 shape of the inner volutions. The writer is not of the 

 opinion that Proclydo7iautilus belongs to the same group as 

 Clydonautihis. This genus is common in the Upper Trias 

 of the Mediterranean region, India and California. 



• 



Proclydonautilus triadicus Mojsisovics. 



Plate XLVI, Fig. 2; Plate XLVII, Fig. 2. 



1873. Nautilus triadicus, Mojsisovics, Das Gebirge um Hallstatt, Bd. I, 



p. 27, pi. xiv, figs. 1-4. 

 1882. Clydonautihis triadicus, Mojsisovics, Cephalopoden d. Mediterranen 



Triasprovinz, p. 281. 

 1902. Proclydonautilus triadicus, Mojsisovics, Das Gebirge um Hallstatt, 



Supplement-Heft, p. 209. 



> See Biblios. 21— p. 281. 



