110 E. W. ELLS ON TITE GEOLOGY OF 



province, on the Vermont boundary, where the equivalent of the Levis formation had 

 been recognized. 



The rocks of the section between Philipsburg (on Missisquoi Bay, the lower north- 

 east extremity of Lake Ohamplain) and St. Armand station, on the line of the Central 

 Vermont railway, consist largely of limestones of various shades of gray with partings 

 of shales. The limestone is in places crystalline and on the eastern portion of the section 

 nearer St. Armand, a well defined synclinal is seen in which beds of dolomitic greyish 

 shales occur, The greater part of the series throughout the section is fossiliferous, and in 

 places fine specimens can be obtained, not only from the weathered surface of the rock, but 

 from the mass itself although the breaking out is sometimes difficult. The fossils obtained 

 are characteristic of the Calciferous and Chazy formations, the latter being abundant in the 

 upper beds, and there is a regular passage apparently from the lower to the higher. 

 Further to the north-east, about Bedford and Mystic, in Stanbridge township, there occur 

 in connection with the upper portion of the section, beds of conglomerate as well, the 

 pebbles, consisting of limestones in a calcareous matrix. The fossils furnished are also 

 of Chazy age, while many of the pebbles contain fossils also of Calciferous age and of a 

 character such as show that they have been derived from the rocks of the Philipsburg 

 section. Large collections of these fossils were examined by Billings and compared with 

 those from the Levis beds, and the similarity was found to be so great that the three hori- 

 zons were regarded as practically identical.' The conglomerates of Stanbridge, however, 

 which yielded Chazy forms from the paste, were held to be newer than the Levis rock, 

 as none of the species which characterize Div. C, which may be said to be the lowest 

 member of the Chazy formation in the Philipsburg section, were recognized in the Levis 

 conglomerates. If now we continue the line of section eastward from St. Armand station 

 we find, after passing a river flat, a ridge of hard dolomitic and silicious rocks, sandstones 

 and slates, sometimes reddish, but more frequently of a greyish colour, which contain 

 fossils of primordial age and which were assigned by Billings to the Potsdam formation. 

 This represents the red sandstone of Vermont and has more recently been examined by Wal- 

 cott, who had found lower Cambrian fossils at various points of the series. The term Pots- 

 dam, as used by Billings, should not, however, be regarded in the limited sense in which 

 it is applied at the present day, since the term was then held to include all between the 

 Calciferous and the Huronian. 



Passing the outcrop of these Cambrian rocks, which is of no great width, we reach 

 at once a series of bluish-grey calcareous and doloiuitic slates which extend thence east- 

 ward to within two miles of Frelighsburg, where they are underlaid by other slates, hard, 

 greyish and siliceous, along with black slates and hard dolomitic beds, the latter also 

 siliceous and veined with white quartz, which constitute a well defined feature for many 

 miles. In the adjoining state of Vermont, near Highgate Falls, Walcott has found upper 

 Cambrian fossils, not only in the black slates associated with the dolomite bands, but in 

 certain associated beds of limestone breccia, thus definitely fixing the horizon of the whole 

 series, while from the area of dolomitic grey slates, which comes between these and the 

 Cambrian axis near St. Armand, Chazy fossils have also been obtained. Thus we haA'e four 

 well defined horizons in this section of fossiliferous rock, all of which can be readily distin- 

 guished and mapped, ranging from the base of the Cambrian to the top of the Chazy. 



' 'Geol. of Canada,' 1863, p. SCO. 



