440 THE CANADIAN NATURALIST. [Vol. vi. 



lower members of the Cambrian. Sir William Logan supposes 

 the appearance of these rocks in their present attitude by the 

 side of the strata of the Trenton and Hudson River-groups, in 

 the vicinity of Quebec, to be due to a great dislocation and uplift, 

 subsequent to the deposition of these higher rocks ; but, as sug- 

 gested in my address of last year, I conceive the Quebec group 

 to have been in its present upturned and disturbed condition 

 before the deposition of the Trenton limestones. The supposed 

 dislocation and uplift, extending from the gulf of St. Lawrence 

 to Virginia, is according to this view, but the outcrop of the 

 rocks of the first fauna from beneath the unconformably over- 

 lying strata of the second fauna. The later movements along 

 the borders of the Appalachian region have however, to some 

 extent, affected these, in their turn, and thus complicated the 

 relations of the two series. This unconformity, which corresponds 

 to the marked bre;ik between the Levis and Trenton faunas, is 

 farther shown by the stratigraphical break and discordance in 

 Herkimer county, Mew York ; and by the fact that beyond the 

 limits of the Ottawa basin, on either side, the limestone of the 

 Trenton group rests directly on the crystalline rocks ; the older 

 members of the New York system being altogether absent at the 

 northern outcrop, as well as in the outliers of Trenton limestone 

 seen to the north oF Lake Ontario, and as far to the north-cast as 

 Lake St. John on the Saguenay. This distribution shows that a 

 considerable movement, just previous to the Trenton period, took 

 place both to the west and the east of the Adirondack region, 

 which formed the southern boundary of the Ottawa basin. 



The Levis and Chazy formations, as we have seen, offer a 

 commingling of forms of the first and second faunas, which shows 

 them to belong to a period of transition between the two ; but it 

 is remarkable that so far as yet observed, no representatives of 

 the later of these faunas are known to the east and south of the 

 Appalachians, along the Atlantic coast; the first fauna, whether 

 in Massachusetts, New Brunswick or southeastern Newfound- 

 land, being unaccompanied by any forms of the second. The 

 third fauna, on the contrary, is represented in various localities 

 both within and to the east of the Appalachian region, from 

 Massachusetts to Newfoundland. In parts of Gaspe, and also in 

 Nova Scotia, strata holding forms referred to the Clinton and 

 Niagara divisions are met with, as well as other beds of Lower 

 Helderberg age, associated with species of shells and of plants 



