464 STRATIGRAPHICAL GEOLOGY. 



older Cambrian of England, and the Levis to the Skiddaw slates, or the lower part of 

 the Cambro-Silurian of America. This view renders it unnecessary to regard these 

 fossiliferous groups as at all connected with the proper Huronian, or the rocks of the 

 two eastern synclinals ; but it shows that inversion is the rule for these rocks near 

 Quebec, and therefore the rocks east of the Sillery are older. This is in agreement 

 with the recently quoted view of Mr. Macfarlane, and has been also insisted upon by 

 Dr. Hunt.* 



Separating the eastern part of the area called Quebec group by Logan, we may 

 clearly understand it to be older than the fossiliferous Cambrian of any part of the 

 world, and therefore to be named Huronian, unless we adopt the suggestion of Mac- 

 farlane. He is probably correct in referring this eastern portion of the Quebec group 

 to the upper division of the Urschiefer, in distinction from the lower, which may be the 

 same with the Michigan rocks. But instead of calling the upper division Cambrian, it 

 is better to say Upper H2ironian ; and, if further examination confirms the suggestion 

 that none of the upper division is to be found about Lake Huron, we may call that the 

 Lower Huronian. Where it is not possible to define between the upper divisions, it 

 will still be proper to use the general term for the whole. Our statements respecting 

 these rocks in New Brunswick indicate the presence of the felsites of the lower divi- 

 sion with the more argillaceous upper group. 



The Vermont Huronian. 



The Vermont Huronian, save that along Connecticut river, is the southward contin- 

 uation of the Quebec group of Canada. It is divided into two parts by the central 

 ridge of the Green Mountains, which continues a few miles into Canada. 



Macfarlane follows the report on the geology of Vermont in regarding the Green 

 Mountain ranges as older than the adjacent Upper Huronian. We have in that early 

 publication (1861) insisted that these Green Mountain rocks underlaid the green schists 

 upon both sides (see p. 31), and they are consequently older. The name Green Moun- 

 tain gneiss, as applicable to this formation, was in use in 1846; and therefore the use 

 of the same geographical designation by Dr. Hunt, in 1871, for the Huronian, is both 

 inappropriate and improper, on account of prior usage. The Green Mountains are not 

 Huronian at all, though flanked by it upon both sides in the northern half of Vermont. 

 They belong to the Montalban series. Adopting the principle of inversion, as applied 

 to the members of the Quebec group, we find they overlie these Montalban gneisses 

 in the proper order of succession. As Macfarlane says, those who once accepted the 

 theory of the metamorphism of New England seem to retain erroneous notions of the 

 age of the successive mountain ranges, calling the Green Mountains newer than the 

 Adirondacks, and the White more recent than the Green. They are both nearer the 

 Laurentian than the Huronian, in respect to age. 



* Chemical and Geological Essays, p. 613. 



