310 THE CAMBRIAN. [boluW, 



foundland and the lower portion of the south shore of the St. Lawrence 

 are absent, and that the section is composed almost entirely of arena- 

 ceous and argillaceous sediments. A limestone conglomerate, near the 

 upper portion of the Sillery, contains bo wlders carrying the Olenellus 

 fauna, and the Upper Cambrian fauna bccurs in the basal conglomer- 

 ates of the Point Levis, graptolitic.Lower Silurian (Ordovician) shales. 

 These bowlders appear to have been derived from a limestone series 

 similar to that now found in Labrador and Newfoundland. 



The strata referred to the Cambrian, on the western side of the Sut- 

 ton Mountain anticlinal or the belt extending southwesterly from Que- 

 bec to the Vermont boundary, consist of more or less of the Sillery 

 series, as found in the vicinity of Quebec; and, according to Drs. 

 Selwyn and Ells, of a subjacent series of hard quartzite rocks interstrat. 

 ified with mica schist and black slate. The volcanic series, referred to 

 the Cambrian in this region, indicates that during earlier Cambrian 

 time the volcanic products were deposited contemporaneously with the 

 included sandstones and slates, thus giving a phase of sedimentation 

 not known elsewhere in the Cambrian of the Appalachian province. 

 For this reason and from the fact that there is not any paleontologic 

 evidence of the age of this volcanic series I am inclined to think that 

 it may belong to some pre-Cambrian terrane. 



Entering the northern end of the valley, between the Green Moun- 

 tains and the Adirondacks, a sudden change occurs in the sedimenta- 

 tion. At the base, the Olenellus fauna ranges through 1,000 feet of 

 magnesian limestone, and for 250 feet higher up in arenaceo-argilla- 

 ceous shales. More or less arenaceous matter is associated with the 

 limestones, and, about 2,000 feet above, a great lenticular mass of lime- 

 stone occurs in the argillaceous shales, in which a fauua of Upper Cam- 

 brian aspect is found. At other localities this fauna occurs in the 

 shales themselves and in a brecciated limestone at the same relative 

 horizon. As far as known the upper portion of the Cambrian is 

 formed of the shales. Proceeding southward and nearer the old coast 

 line ift Addison County, Vermont, the limestone series is found to 

 graduate into the Granular Quartzite or the beach sand. From this 

 point this shore deposit is traced without interruption to the Massa 

 chusetts boundary; and then, with more or less interruption, to the 

 Hudson River below Ponghkeepsie, New York. It is taken up again 

 in New Jersey, and thence may be followed, with some interruption, 

 across Pennsylvania to Maryland, whence it extends as an almost 

 continuous formation across Virginia into Eastern Tennessee, and 

 thence, with some interruption, into Georgia andAlabama. On all this 

 long line it forms the basal member of the Cambrian ; and wherever fos- 

 sils have been found in it they belong to the Olenellus or Lower Can> 

 brian fauna. 



The offshore, or deeper water deposits, are represented by finer- 

 grained sandstones, shales, slates, and limestones. In southern Ver- 





