124 E. W. ELLS ON THE GEOLOGY OF 



and labelled as belougiug to the same series. As the determinations of Hall, in 1855, 

 were made on specimens obtained before the stratigraphical sequence was properly under- 

 stood, and, in fact, while the whole of the series was regarded as representing the Hudson 

 Kiver formation of the New York geologists, and as to a certain extent the same remarks 

 apply to the collections examined by Lapworth, it is but natural to expect that a certain 

 amount of confusion should exist. 



In regard to the determination of the graptolites, it must, however, be admitted that 

 this paper of Lapworth's is of very great valtie. The relative positions of the zones, as 

 determined by the limited number of fossils submitted to him, since, however, largely 

 increased, has been very closely confirmed by the most recent stratigraphical conclusions ; 

 and when certain at present somewhat obscure points are more carefully worked out, 

 there will probably be but little to correct in the determination of the organic remains 

 from this group. In the grouping of strata, as given in his paper, however (see p. 174), 

 certain corrections must be made, since he has there included in the upper part of his 

 lower division (C), a Levis division of the Cambro-Siluriau above the Levis graptolites, 

 a great part of the Sillery beds which we now know to be beneath the Levis stratigra- 

 phically ; while in the Cambrian division (B), he has incorporated a part of the same 

 Sillery formation. This error plainly arises from following the divisions published in 

 ' The Geology of Canada,' 1863, p. 227, too closely. 



With these exceptions, the stratigraphical arrangement as contained in pp. 173-175 of 

 his paper will be in very close conformity with that lately published in the Geological 

 Survey reports, and which may be briefly summed up as follows : 



1st and at the base. The crystalline schists of Sutton mountains, the Buckland hills and 

 the Shickshock range, of iire-Cambrian age. 



2. The green, black and purple slates, often quartz veined with hard quartzites, shading 



upward into the red and green shales and green sandstones and limestone con- 

 glomerates of the Sillery, with Obolella preliosa, Lingula, sponge spicules and 

 small trilobites, Agnostus, etc., and in the pebbles of the conglomerate OleneUus 

 Thompsoni and other Lower Cambrian trilobites, the whole of which can be 

 classed as of Cambrian age. 



3. The green, grey and black fucoidal and graptolitic shales of the Levis formation, with 



their associated characteristic limestone conglomerates, in which the pebbles con- 

 tain fossils of Potsdam age and the matrix others peculiar to the Cakiferous form- 

 ation. These constitute the lowest members of the Cambro-Siluriau orOrdovician 

 system, and are the stratigraphical equivalents of the Calciferous formation found 

 in the lower part of the Philipsburg section and in the state of New York. 



4. The dolomitic slates and limestone conglomerates of Stanbridge township, with certain 



black and grey slates, which form the upper part and in which the characteristic 

 of the township fossils are of Chazy age. 



5. Black limestones and slates of Farnham, Eichmond, Danville, Hatley, Eaton, etc., also 



fossiliferous and abounding in graptolites in certain places of Trenton ago, and, 

 possibly, in part of the Trenton-Utica. To these, also, may for the present be 

 assigned the rocks of the city of Quebec, of the north-west end of the Island of 

 Orleans, the patches of Trenton-Utica seen on the north side of Gaspé peninsula 

 and the great stretch from Marsouin river to near Cape Rosier (Marin Brook). 



