474 C. D. Walcott — Cambrian Rocks of Pennsylvania. 



ville with the massive Scolitlms quartzite of the Hellam hills. 

 In passing from Pleasureville towards York, on the steep side 

 hill two miles west of York there are exposures in the road- 

 side of shales and calcareous sandstone above the massive 

 quartzite of the Hellam hills. At a point probably 100 feet 

 beneath the ferriferous shale in which the numerous'ore pits 

 occur on the south side of the Hellam hills, a species of 

 Oboletta, very closely allied to Obolella crassa, and fragments 

 of Olenellus were found in the decomposed calcareous sand- 

 stone. At a locality about one mile south of Mt. Zion church, 

 in Hellam township, and four miles northeast of York, numer- 

 ous specimens of Camerella minor and fragments of Olenel- 

 lus occur in a calcareous quartzite identical in character with 

 that of the Emigsville section. These two localities prove 

 that the Scolitlms quartzites of the Hellam hills and of 

 " Chiques Rock " are beneath the Olenellus calcareous quartz- 

 ite of the Emigsville section and, therefore, of Lower Cam- 

 brian age. 



Search was .next made for fossils near the base of the lime- 

 stone above the ferriferous shales resting on the quartzites of 

 Hellam hills. They were found at a short distance above the 

 shales in a small quarry of thin-bedded limestone by the road- 

 side, one and one-eighth miles north of Stoner's station on the 

 York & Wrightsville railway. The strike is a little north of 

 west, and dip 45° south. Finely preserved specimens of 

 Linnarssonia, closely allied to Linnarssonia sagittalis are 

 abundant, and easily recognized fragments of a species of 

 Olenellus are associated with them. Crossing the section to 

 the south, occasional exposures were seen of massive bedded, 

 light-colored limestones, much of the same character as those 

 exposed in the quarries north of Wrightsville three miles to 

 the eastward. The dip increased to 85° at the railroad track, 

 which indicated that a compressed synalinal had been passed 

 over in the section. The only locality where fossils were 

 found within the main body of the limestone in York County 

 was one and one-half miles southwest of the public square at 

 York, Pa., on the north side, of Highland Park. The species 

 recognized are : one closely allied to Olenoides Ma?*cotd, Pro- 

 typus senectus, and two species of Ptychoparia, all of which 

 belong to the Lower Cambrian fauna. When examining the 

 section on the east side of the Susquehanna, in Lancaster 

 county south of Columbia and north of Washington Manor, 

 with Messrs. A. Wanner and Arthur Keith, a locality of lower 

 Cambrian fossils was found in a narrow belt of limestone 

 about half a mile north of Washington Manor. Hyolithes 

 communis and fragments of Olenellus showing portions of the 

 head and thoracic segments were recognized in the material 

 collected. 



