1853.] BIGSBY GEOLOGY OF QUEBEC. 85 



about Beauport, and is particularly well seen in the Rivers Mont- 

 morenci, St. Charles, and Petite Ruisseau. 



TJtica Slate. — Utica slate has been recognized here by the best 

 observers in a uniform dark shale, with few fossil remains (Tri- 

 arthrus Beckii) ; but it must be of small thickness (though not 

 yet ascertained), because in this vicinity it soon loses its character- 

 istic* of never containing fragments of other rocks. It is, in fact, a 

 development of the shaly part of the Trenton limestone, interposed 

 between the limestone and the next series of strata, the Hudson 

 River group ; and it, therefore, may here be considered as a thin band 

 between the Trenton limestone and the Hudson River group, into 

 which its passage is gradual. 



Hudson River Group. — The Hudson River group (Caradoc sand- 

 stone of Wales) occupies large portions of the north shore of the 

 St, Lawrence and all the region south of this river, for more than 

 100 miles in all directions. 



The northern boundary in the environs of Quebec (see Map) may 

 be thus stated. It crosses the river from the seigniory of Tilly on 

 the south shore, 14 miles W.S.W.^W, of Quebec, a little to the 

 west of St, Augustine's church, 4| miles above Cape Rouge, and then 

 bends round to the N.N.E, by Old Lorette, traverses the River St. 

 Charles, one mile (or less) below Indian Lorette, and continues 

 E.N.E, to the Mill of Charlesbourg. From hence eastwards, it 

 strikes the River des Anges a few hundred yards above the King's 

 Mill, and afterwards (obscured by Drift) proceeds to the beach of 

 Quebec Basin, west of, and near to the mouth of Beauport River. 

 It is from thence continued as a narrow border southwestward along 

 the Canardiere ; and northeastward, along the edge of the basin, to 

 Montmorenci, Ange Gardien, and so on for many miles. 



Both the Utica slates and the Hudson River group correspond in 

 this neighbourhood in all essential particulars, in their fossil contents, 

 mineral structure, and habits, with their prototypes of New York, 

 and they have been received as such by Professors Emmons and 

 Mather, and by Sir Charles Lyell, 



From the continual alternation in single layers, or in sets, of all the 

 strata composing the Hudson River group of this region, — from 

 their occasional recurrence at distant intervals in the same or nearly 

 the same forms, — from their mutually affecting each other's compo- 

 sition, — and from their general conformability, the same general 

 epoch must be assigned for the deposition of the whole, however vast 

 the space they cover. 



The only stratum that seems to require description is the sand- 

 stone, which was form rly called " greywacke." Its aspect is more 

 that of a grit than of a sandstone. It is an aggregate of oblong or 

 rounded masses of hyaline quartz, varying from a microscopic size to 

 that of a horse-bean, or even of a walnut ; but a pin's head or a pea 

 represents their most common size. This rock contains worn frag- 

 ments of brown and black quartz ; and, in separate localities, a little 



* Vaniixem, Geol. Reports of State of New York, p. 56. 



