198 The American Geologist. Mareh, 1892 
EDITORIAL COMMENT. 
THE SO-CALLED LAURENTIAN LIMESTONES AT ST. JOHN, NEW 
BRUNSWICK. 
We are obliged to Prof. Matthew for stating concisely the evi- 
dence of the Archean age of the limestones which at St. John 
contain the newly discovered fossils mentioned in the GEOLOGIST 
for January, p. 55. We do not intend to take issue strongly with 
Prof. Matthew on a question pertaining to the geology of his own 
region. We only intended, in our note calling attention to the 
possible primordial age of the fossils he has described, to direct 
his attention to the lack of demonstration that they are of the age 
to which he has assigned them. Since he has taken the pains to 
question the validity of our doubt, we will state more fully the 
several facts which form its basis: 
1. The base of the Taconic (which here we use as equivalent 
to primordial), is everywhere a quartzyte associated with a lime- 
stone. Usually the limestone overlies, but in some cases it is in- 
terbedded with or blended with the siliceous rock, constituting a 
fine-grained cherty limestone. It is not necessary to mention all 
the localities where this is known to be the succession. In Ver- 
mont it embraces the Granular Quartz and the Winooski marble, 
followed by a series of reddish, tufaceous, siliceous sandstones 
and shales which are probably the remote effects of oceanic vol- 
canoes which broke out immediately after the deposition of the 
Winooski limestone. It is a desideratum to ascertain the strati- 
graphic succession from the limestone to the chronologically over- 
lying strata in the Vermont district, but further south Prof. Dana 
has traced the limestone (under the name of Stockbridge lime- 
stone) through Massachusetts and Connecticut to Courtland, N, 
Y., where he found it upheaved and overwhelmed in the eruption 
of the Courtland gabbros. Intermediate points indicated that 
they took on the aspect of crystalline rocks, and indeed that much 
of the +‘ Laurentian” of western Massachusetts and Connecticut 
(in which to this day no fossils have been found) is of the age, ex- 
actly or nearly, of these basal Taconic rocks. The mineral chon- 
drodite was considered diagnostic of the Laurentian age of this 
limestone. 
2. In Vermont characteristic Taconic fossils have been found 
