1897] Ells — Recent Conclusions in Quebec Geology. 175 



other lower Cambrian fossils. Tn point of time the Levis beds 

 may be regarded as the equivalents of the Calciferous of the 

 Ottawa Basin, while the lower portion or upper Sillery may be 

 taken as the equivalent of the Potsdam sandstone. 



The rocks of Quebec City and the Citadel Hill are some- 

 what higher in the scale than those of the Levis shore opposite. 

 They were at first regarded as of Levis age and lower in posi- 

 tion than the Sillery. Subsequently they were held to repre- 

 sent the Hudson River and Utica divisions, but a careful study 

 of the fossil contents, as well as of the stratigraphical relations 

 as shewn in other portions of the field, where the similar rocks 

 appear,shews this peculiardevelopmentof strata tobelong largely 

 to the lower division of the Trenton and not far from what is de- 

 signated the Black River division. The equivalence of the 

 areas in the vicinity of Quebec to those seen in the Phillipsburg 

 section has also been very clearly established, and the rocks of 

 the latter are found to range upward from the base of the Cal- 

 ciferous to the top of the Chazy formation. Thence eastward 

 the ascending sequence can be traced upward into the black 

 slates and limestones of Farnham which are apparently the 

 equivalents of those of Quebec city, but which were at one time 

 described as a part of the Potsdam formation. 



The great areas of upper Silurian, once depicted on the 

 map of the province of Quebec, have in large part been re- 

 moved. These were supposed to occupy the greater portion of 

 the province, east of the Sutron mountain range ; and their 

 Silurian horizon was maintained from the presence of a number 

 of areas of these fossiliferous rocks found at various places in 

 this district. The detailed study of this field shewed conclusively 

 that these Silurian areas were detached outliers, sometimes of 

 very limited extent, in places infolded with the underlying 

 Cambro-Silurian sediments. The age of the latter was estab- 

 lished by the finding of characteristic fossils, such as graptolites 

 and trilobites at a number of points. It can therefore be safely 

 asserted that by far the greater part of the area east of the Sut- 

 ton Mountain anticlinal is occupied by strata of Cambro Silurian 

 and Cambrian age and that the upper Silurian and Devonian 

 portions are very limited in extent. 



The question of the age of the mountain masses of diabase 

 and syenite so conspicuously displayed in the area east of the St. 

 Lawrence, has also been a somewhat difficult one to decide. In 

 places the associated rocks have been so altered as to present the 



