16 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 76 



Petoskep iormation — Continued. 



Zones undetermined — Continued. 



zoa, crinoid joints, two species of Cyrtina, Taeniopora, many types 

 of Stroniatopora, Aulopora, Striatopora, Certopora erccta type, Cysti- 

 phylluin, CylindrophyUum panicum Winclieil, and a smaller species, 

 FenesteUa, Atrypa, Athyris, Cramiena (with fine color bands), Pholi- 

 dostrophia (flexed type), Conocardium species, Phacops, Athyris, and 

 Cystodictya 3 feet 6 inches. 



Bed 7. Soft, fissile, black shale without fossils, containing inch-thick 

 calcareous lenses with Spirifer cf. mucronatus, and Fenestellids, 

 6 inches. 



Bed 6. 'Buff, fine-grained, fragmental limestone in single bed becom- 

 ing shaley at top. Mucronate Splrifer (most common), Favosltes 

 (arbusculate type), Ceratopora, Heliophrentis, Aulopora, many Tre- 

 postomes, Sfromatopora (Idiostrowa type), Gypidula, Stropheodonta 

 erratiea, digitate Favosites, Phacops species and Striatopora 3 feet. 



Bed 5. Crinoidal, fragmental limestone in thick beds, bluish grey 

 weathering brown. Fauna as below with new elements, i. e., small 

 Cyrtina, FenesteUa, large, high-areaed Spirifer, and numerous species 

 of Trepostomes 5 feet. 



Bed 4. " Gypidula Bed." Slightly calcareous shale doming in floor of 

 quarry. Extremely fossiliferous but with few species. Great abun- 

 dance of Oypidula, fine lined Spirifer, large, mucronate Spirifer, 

 deeply sulcate Athyris, broad fronded Cystodictya Quarry floor. 



At the top, as at the base, of this section there is again an hiatus of 

 undetermined extent between it and the next succeeding continuous 

 section. Unfortunately for the study of the stratigraphic succession 

 in this area the thick covering of drift to the south of the narrow 

 belt of hard-rock formations bordering Little Traverse Bay hides 

 the uppermost beds of the Traverse group. These are exposed at but 

 one locality, near the Antrim — Charlevoix County line just north of 

 Norwood. This exposure is, incidentally, at the same time the 

 westernmost and southernmost outcrop of " in situ " Traverse rocks 

 in western Michigan. The location of rocks of this age in Benzie 

 and Leelanau Counties and on the Manitou Islands on the State 

 geological map is purely inferential. 



Geological section on shore of Lake Michigan, 1 to 2 miles nortli/west of 

 Norwood {locality 7c) 



Running north along the shore of Lake Michigan for about a mile from a 

 point nearly a mile northwest of Norwood are beds dipping in a south- 

 west direction and forming bluffs at its northern edge of exposure of nearly 15 

 feet in height above lake level. A point at the northern end of exposure, extend- 

 ing slightly into the lake, exhibits the lowest beds of the section dipping at an 

 angle of about 20° to the south. These beds carry an abundance of small 

 Atrypas. Lithologically there is no distinct difference between these layers 

 and the next succeeding, which are, however, characterized by numerous digi- 

 tate Favosites. The basal foot and a half of this latter bed is practically 

 barren and is composed of a light grey, dirty, limey shale, but the upper 6 

 inches are full of fossils, the upper surface of the bed being covered with 



