466 ADDRESS OF T. STERRY HUNT. 
ers, as now by Safford, looked upon as wholly of Potsdam age, in- 
cluding the Scolithus sandstone as a subordinate member, so that 
the strata beneath this were still regarded as belonging to the New 
York system. Hence, while Rogers inquires whether the Taconic 
system “‘may not along the western border of Vermont and Mas- 
sachusetts include also some of the sandy and slaty strata here 
spoken of as lying beneath the Potsdam sandstone”’* he would still 
embrace these lower strata in the Champlain division. 
Thus we see that at an early period the rocks of the Taconic 
system were, by Rogers and Mather; referred to the Champlain divi- 
sion of the New York system, a conclusion which has been sus- 
tained by subsequent observations. Before discussing these, and 
their somewhat involved history, we may state two questions which 
present themselves in connection with this solution of the problem. 
First, whether the Taconic system, as defined by Emmons, includes 
the whole or a part of the Champlain division ; and second, wheth- 
er it embraces any strata older or newer than the members of this 
portion of the New York system. With reference to the first 
question it is to be remarked that in their attempts to compare the 
Taconic rocks with those of the Champlain division as seen farther 
to the west, observers were led by lithological similarities to iden- 
tify the upper members of the latter with certain portions of the 
Taconic. In fact, the Trenton limestone, with the Utica slates 
and the Loraine or Hudson River shales, making together the upper 
half of the Champlain division (in which Emmons moreover in- 
cluded the overlying Oneida and Medina conglomerates and sand- 
stones), have in New York an aggregate thickness of not less than 
three or four thousand feet, and offer many lithological resem- 
blances to the great mass of sediments at the western base of the 
Green Mountains, to which the name of Taconic had been applied. 
It is curious to find that Emmons, in 1842, referred to the Medina 
the Red sandrock of the east shore of Lake Champlain, since show? 
to be Potsdam ; and, moreover, placed the Sillery sandstone of the 
neighborhood of Quebec at the summit of the Champlain division, 
as the representative of the Oneida conglomerate ; while at the 
same time he noticed the great resemblance which this sandstone, 
with its adjacent limestones, bore to similar rocks on the confines 
of Massachusetts, already referred by him to the Taconic system. t 
a a 
* Amer. Jour. Sci., I, xlvii, 152, 153. 
t Geol. Northern District of New York, pp. 124, 125. 
