278 THE CAMBRIAN. (uuu..8i. 



The Georgia slate series, according to Prof. C. H. Hitchcock, consist 

 in Vermont of several varieties of rock. 1 They are (1) clay slate; (2) 

 roofing slate ; (3) clay slate approximating to micaceous sandstone ; (4) 

 various kinds of limestone; (5) brecciated limestone ; (G) conglomerate 

 formed of pebbles of limestone. 



A carefully measured section extending up through the " lied Sand- 

 rock " and Georgia series, beginning at the base of the western face of 

 the cliff overlooking the level that reaches to the shore of Lake Cham- 

 plain, in the town of Georgia, Franklin County, Vermont, and extend- 

 ing southeastward to Parker's quarry, a little south of the Georgia 

 post-office, gives the following: 2 



Feet 



(1) Massive bedded, bluish gray dolomitic limestone, with many inosculating 



threads and bunches of a yellowish-drab sandy limestone that weathers 



in relief 3 35 



(2) No. 1 passes into a steel-gray dolomitic limestone that weathers to a dark 



buff and bluish black, with angular fragments of bluish gray limestone 

 appearing irregularly at the surface. At 160 feet from the base the first 

 band of mottled limestone, "Calico" or Winooski marble, is met with. 

 The latter grades into a reddish dolomite, free from mottling, and then in 

 a gray limestone. (Fossils, Hyolithellus?) 200 



(3) Gray dolomitic limestone in massive layers, some of which are mottled, red- 



dish and white, but the larger part are gray and yellow. Many of the 

 gray layers break up into a columnar structure, the columus being at 

 right angles to the bedding. In a reddish-colored limestone, 200 feet from 

 the base, a slender elongate tube occurs, probably Hyolithellus micans . . . 475 



(4) Reddish pink, dolomitic limestone, weathering to a reddish brown and de- 



composing on the exposed edges to an arenaceous, dark, brownish-red 

 rock that shows numerous fragments of fossils: Kutoryina labradorica, 

 Obolella (?) sp., Salterella pulchella (?), Ptychoparia adamsi, Olenellus 

 thompsoni 100 



(5) Gray arenaceous limestone in rough, massive layers, passing into more 



evenly bedded, light gray, arenaceous limestone. Fossils similar to those 



in 4 occur in the lower portion 190 



Total thickness of limestone 1,000 



(6) Georgia shales. — Argillaceo-micaceous and arenaceous shales, containing 



numerous fossils, at Parker's ledge, and showing deposition contact on 



No. 5 200 



Strike at Parker's Quarry, N. 30° E., dip 8° to 12° E. 



The fossilifero us shales at Parker's Quarry contain : Palwophycus in- 

 cipiens, P. congreyatus, Diplograptus sinqrfcx [now, 1831, Pkyllograptus (?) 

 cambrensW], Climacograptus (?) emmonsi, Kutorgina cingulata, Orthisina ori- 

 entalis, O. festinata, O. transversa, O.sp. (?), Microdiscus parkeri, Mesonacis 

 vermontana, Olenellus thompsoni, Olenoides marcoui, JBathynotus holopyya, 

 Ptychoparia adamsi, P. vtdvanus, Protypus hitchcocki, P. senectus, and 

 P. senectus var. parvulus. 



1 Hypozoic and Paleozoic rocks. Report on the geology of Vermont, vol. 1, 1861, p. 358. 



2 Walcott, C. D. Second contribution to the studies of the Cambrian faunas of North America. U. 

 S. Geol. Survey, Bull. No. 30, 1886, pp. 15, 17. 



3 A mile south of the lino of the section about 75 feet of arenaceous limestone occurs beneath this 

 bed. Fifty feet from the base I found during the summer of 1890 Obolella erased f, Salterella sp. 1 

 Hyolithes 2sp., and fragments of a apecies of Olenellus. A few feet higher in the section the heads of 

 Protypus sp. ? and of Olenellus sp. ? were found. Traces of the Olenellus fauna were also found at point* 

 85, 153, and 193 feet above the lowest horizon. 



