Editorial Comment. 199 
by Mr. Walcott in this quartzyte, and in northwestern New Jersey 
they have been found by Mr. Beecher in the same strata «ssoci- 
ated with chondrodite. These strata are unconformable below the 
later series at Rutland, Vt. 
3. The Courtland (N. Y.), gabbros are repeated, and of the 
same age, in the Adirondacks. ‘They here broke out at the same 
date and buried these strata under immense floods of eruptive 
rock. Asin Vermont and in eastern New York this horizon is 
the great iron-bearing horizon of the region; but in northeastern 
New York an element is introduced into the iron which is not 
found when there was no actual outflow of basic rock, viz., titanic 
ores abound, these being a characteristic native element of gabbro. 
4. It is only recently that the effect of this early Taconic 
eruptive period has been located farther north, r/z., in the St. 
Lawrence valley. Mr. Ells has carefully described the so-called 
‘Quebec Series’ of the Canadian geologists. He has found the 
primordial portion of it to consist of two parts, v/z., a series of 
shales and sandstones, and a series of quartzytes and limestone, 
the latter series being unconformable below the former, This un- 
conformity we take to mark the date of outbreak of the Adiron- 
dack and Courtland eruptives, and especially so as the rocks are 
said to contain large admixtures of volcanic materials, and as the 
lower strata are lithologically identical with those which ante- 
dated that outbreak in Vermont and New York. The red shales 
of the upper Sillery are the Georgia shales and sandstones of Ver- 
mont. : 
5. Without referring to intermediate localities, the strati- 
graphy of which might be considered, in this review, of question- 
able purport, we will mention only the succession in the North- 
west. In northern Wisconsin, according to Prof. Van Hise, not 
only are the basal rocks of the upper iron-bearing series (the Ta- 
conic) a cherty limestone and a quartzyte, but an erosion tnterval, 
introducing a distinct non-chronologic succession and an wneon- 
formity, separates them from the later strata of what he has called 
Huronion but which we consider the later Taconic. Although 
there is a belt of gabbro rocks at other points in Wisconsin their 
relation to this erosion interval and to this non-conformity has not 
been pointed out by the Wisconsin geologists. 
6. However, on the north side of lake Superior, where Prof. 
Matthew has described primordial fossils from the strata succeed- 
