262 DR. THOMAS STERRY HUNT ON THE 
Billings, presents, in its western portion, the whole succession of the Champlain subdivi- 
sions, from the Potsdam to the Loraine shales. Farther eastward on this line, a great 
dislocation brings up the Red Sand-rock, with Olenellus, causing it to overlie, in seeming 
conformity, the Loraine shales. This sand-rock is followed to the eastward by limestones 
holding the fauna of the Calciferous Sand-rock, with other forms like those of the Levis 
limestone. To these succeed other limestones, with an abundant Trenton fauna, interrupted 
by asecond fault, which again brings up the Levis beds; the Sillery sandstone being 
unrepresented, unless possibly by the Red Sand-rock to the west. For a summary of the 
observations on this section, and reference to the original paper, see Azoic Rocks, page 119. 
$ 119. Other examples of an extension of the Ordovician sediments eastward are found 
in the province of Quebec, in various localities along the disturbed region northeastward 
from Lake Champlain. Lying alike among the uncrystalline strata of the Graywacke 
series, and the older crystalline rocks to the southeast of them, there are met with, in many 
localities, carbonaceous shaly beds, more or less calcareous, containing organic remains of 
Ordovician age. These strata, probably never very considerable in amount, have, however, 
rarely escaped erosion, except in localities where, as the result of the folds and dislocations 
already noticed, they have been protected by the overlying or adjacent older strata, beneath 
which they often seem to pass with an eastward dip. As studied at Farnham, in the 
province of Quebec, they thus appeared to be more ancient than the Graywacke series, and 
were described by Logan as portions of Potsdam rocks underlying the Quebec group. The 
black slates of this locality, however, contain, according to Billings, besides undescribed 
eraptolites, Ptilodictya, and trilobites of the genera Ampyx, Dalmanites, Lichas, Triarthrus and 
Agnostus ; and were hence referred by him to the Trenton or the Utica division of the New 
York system. Similar black slates appear, in like manner, to pass beneath the crystalline 
schists which lie to the east of the Graywacke-belt in this region, and were by Logan 
adduced as proofs of the view then maintained by the geological survey of Canada, that 
the crystalline rocks in question were nothing more than portions of this same Graywacke 
in an altered condition. 
The fallacy of this view I have long since shown, and have pointed out the nature of 
the stratigraphical accidents by which this seeming inversion has been brought about. 
Selwyn, the present director of the geological survey of Canada, has furnished additional 
facts regarding the distribution of these fossiliferous shales ; outliers of which have been 
observed at various localities in eastern Canada, among the crystalline schists, especially 
along the west side of a line of fault, with an upthrow on the east side, extending through 
Stukley and Ely. Similar fossiliferous beds are found in Tingwick and Arthabaska, and 
also near Richmond; where a narrow belt of black shales with Triarthrus, and other organic 
forms, is found lying to the east of the crystalline schists of the region. The latter are a 
second time brought up on the eastern border of these shales, and soon pass beneath the 
argillites of the Windsor basin (§ 81). 
In this connection it may be noticed that Dodge has lately found, still farther to 
the eastward, in Penobscot County, Maine, black shales holding graptolites, which are 
regarded by him as species belonging to the Utica slate.* 
§ 120. It was said at the commencement of this essay, that the Upper Taconic rocks 

*Amer. Jour. Science, 1881, vol. xxii., p. 434, 

