Miller on the Taconic 241 
clearly marked if the Stockbridge limestone had been retained 
in the Upper Taconic. The Paradoxides beds at Braintree, 
Mass., in Newfoundland and New Brunswick, and wherever 
found on the continent, belong to the Upper Taconic. The 
same difficulty exists in the west in separating the Upper Ta- 
conic from the overlying rocks of the Potsdam, that has led to 
so much discussion in the east, and the confusion is increased, 
by the addition of numerous synonyms — the ready weapon to 
to which ignorance resorts. 
In 1863 G. F. Mathew named the rocks exposed at St. 
John's, New Brunswick, the " St. John's group." He described 
them as arenaceous, argillaceous and carbonaceous shales and 
clay slates, often sandy, with sandstone and quartzyte, having 
a thickness of 4500 feet, and an exposure about 30 miles long 
and four miles w^ide. He collected Paradoxides^ Conocefhal- 
ites^ Obelella^ Orthis Orthisina^ Disci?ia, Hyolithes^ and Lin- 
gula. In 1865 he and Bailey and Hartt correlated these rocks 
with the slates of Vermont having Ole7ielliis {^Ellifsocephalus^ 
asaphoides, and the schistose beds at Braintree, Mass., holding 
Paradoxides harlani\ thus proving their "St. John's group," to 
be a synonym, for Emmons "Black slate" in the Upper Ta- 
conic system. Furthermore, they identified the slates with 
some found in Newfoundland containing Paradoxides and 
Cojtocep halites. Later, they divided the Lower Taconic of 
New Brunswick, which they called Huronian, into the " Cold- 
brook group," the "Coastal group," and the "Kingston group," 
and estimated the thickness as exceeding 10000 feet. 
The Vermont geologists in 1861 called the Black slate, Ta- 
conic slate and Roofing slate of Emmons, the "Georgia 
group." The name Taconic has priority over the " St. John's 
group," and if the Taconic system is to be divided into groups, 
with geographical names, and three divisions of Emmons are 
to be thrown together in one group, then they must, under the 
laws of nomenclature, bear the name of the Georgia group. 
The Black slate has however been called the Swanton group, 
and if this name should become desirable, then the Upper Ta- 
conic would be divided into the Swanton group and the Geor- 
gia group; and their maximum thickness in Vermont exceeds 
two miles. This division is that adopted by Perry, who has 
