Belated Formations. 



3 



of its presence, with its lower division the Utica slate, in the valley 

 of the Hudson, was very complete, and, judging from the writings 

 of his associates on the geological survey and contemporary writers, 

 accepted as conclusive. Of the controversy which arose at the time 

 of the making up of the Quebec group, regarding the age of these 

 rocks along the Hudson and the retaining of the term Hudson River 

 group in geological nomenclature, a very complete review will be 

 found in a paper recently published by Prof. James Hall.' 



Passing to the south-west along the line of the Appalachians, we 

 find the Utica slate mentioned by Prof. H. D. Rogers, as occurring in 

 the long valleys crossing the southern, central half of the state of 

 Pennsylvania and into Virginia. In the Kittatinny and Kishico- 

 quillas valleys it has a thickness of from 300 to 400 feet and carries 

 graptolites, also Triarthrus JBecJci. 



South-westward in Virginia the black slate passes into the drab 

 colored shales of the Nashville group of Tennessee, reference to 

 which will be made in reviewing the formations of the Utica slate 

 horizon. The northern extension of the formation from Baker's Falls, 

 Saratoga county, is seen in the numerous outcrops in the Champlain 

 valley and down to the St. Lawrence river, where it expands and 

 extends from Montreal to below Quebec. An outlier at Lake St. 

 John, and the presence of the slate in the channel between the Min- 

 gan Islands and the Islands of Anticosti, gives the known extension 

 to the north and north-east.'- Of its presence at Anticosti Sir William 

 Logan says :^ 



"Loose fragments of black, strongly bituminous graptolitic shales, 

 in every way resembling those of the Utica formation, and of some 

 of the interstratified beds of the Hudson River, are met with on the 

 beach on the north side of Anticosti." 



Graptolites abound at Lake St. John and Triarthrus BecJci also 

 occurs. West of Montreal numerous outliers of the Utica slate are 

 found in the Ottawa basin. Asaphus Canadensis^ which occurs so 

 abundantly at Collingwood on Georgian Bay, is found near the city 

 of Ottawa associated with Triarthrus Becki and other characteristic 

 fossils of the Utica slate formation. 



^ Proceed. Amer. Assoc. Adv. Sci. 1877. 



2 Professor 0. H. Hitchcock, in the Science Neios of March 15, 1879, states that 

 Professor B. K. Emerson of Amherst C'ollege, has in his possession specimens of 

 Triarthrus Becki CUmacograptus hicornis, etc., from the Arctic regionsbr ought 

 by Captain Hall; thus provinor the presence of the Utica slate horizon to the 

 north of any previous known exposure. 



3 Geology of Canada, p. 221.' 1863. 



