M ETA M ORPHIC SERIES OF SHASTA COUNTY. 605 



Hosselkus limestone. The local names given by J. S. Diller 1 to 

 strata in Plumas county are used here because in Shasta county 

 the lithology and fauna are similar. 



The Swearinger slates. — The Swearinger slates consist of 

 about 200 feet of thin-bedded shales, at the top becoming very 

 calcareous, and at the base containing beds of tuff. There are 

 two main divisions, the Tracliyceras homfrayi beds and the Halobia 

 slates. The Tracliyceras homfrayi beds contain great numbers of 

 Tracliyceras homfrayi, Gabb, Lima conf. acuta, Hyatt, and a few 

 specimens of Monotis subcircularis, Gabb, Pecte?i sp., Halobia rugosa, 

 Guembel, Halobia superba, Mojsisovics, et cetera. In some tuffs 

 in this series were found: Spirifcrina sp., and crinoid stems. The 

 fauna is similar to that of the Monotis beds of Genessee valley, 

 Plumas county, as described by Hyatt, 2 and is unquestionably of 

 Noric age. 3 The genus Monotis is very rare in the Pitt region, 

 although very common in the region of Taylorsville, but enough 

 species were found to identify the horizon. The Tracliyceras 

 homfrayi beds with some tuffs make up the lower hundred feet of 

 the Swearinger slates. The upper hundred feet of this division 

 is made up of the Halobia slates. These strata are very calcar- 

 eous, and usually rich in fossils, although these are mostly not 

 well preserved. From their nature these beds are seen only as a 

 fringe along the base of cliffs of the Hosselkus limestone, and 

 are usually covered with talus, so that outcrops are rare. They 

 are filled with casts of Halobia superba, Mojsisovics, with also a 

 few specimens of Rhynchonella sp., Polycyclus Tracliyceras conf. 

 ladinum, Mojsisovics, Eutomoceras, et cetera. According to 

 Mojsisovics, 4 Halobia superba is characteristic of the lower 

 Karnic, and H. rugosa of the upper Karnic, but Dr. Rothpletz 5 

 'Bull. Geol. Soc. Am. Vol. III., p. 372. 



2 Bull. Geol. Soc. Am. Vol. III., p. 397. 



3 The term Noric is used in this paper as it was used by Mojsisovics, and not 

 Bittner. 



•»Abhandl. K. K. Geol. Reichsanstalt, Wien, Bd. VII., No. 2, p. 37. 



s Palseontographica, 39 Band, 1892, p. 91, "Perm, Trias and Jura formation auf 

 Timor." 



