152 References to North American Localities. 
ite, which is imbedded in argillite. It is unquestionably a veg- 
etable petrifaction, and exceedingly abundant throughout more 
than two thousand square miles of surface. This being, geolo- 
gically, the lowest rock in North America, which contains organi- 
zed remains, its meeting with the primitive limerock, is the meet- 
ing of the primitive and transition strata. 
In tracing the localities of the meeting of these classes, we 
will begin at West Stockbridge, where we began with the prim- 
itive limerock; because the argillite is co-extensive with that 
limerock. It runs north, and forms. the vast prominences called 
Bird’s Mountains, between Rutland and Poultney in Vermont. 
It continues northerly, with various degrees of elevation, toa 
great distance into Canada. Jt runs southerly, on and near the 
east boundary of the state of New York, curving westerly along 
the westerly side of Taughconnuck Mountain, its western part 
forming the banks and bed of Hudson River. Its eastern limit 
is between Newburgh and the Highlands, where its meeting with 
the primitive limerock is very manifest. Poughkeepsie on the 
east side of the Hudson, and Newburgh on the west, stand on the 
argillite. 
Limit between Transition (Hemilysient) and Secondary, lower 
and upper (Abyssient and Pelagient) rocks. 
- In article No. IV, published in Vol. xxxvi, p. 61, and note, p- 
198, of this Journal, I endeavored to prove that the rock which 
I had named Corniferous Limerock,* is the best North American 
standard of reference for making out our equivalents to Europeatt 
rocks; particularly as it is Brongniart’s upper transition rock.+ 
Unless state geologists are to abandon geology as a science, and 
to amuse us with local names, insulated and heteromorphous it 
character, they must make it their chief object to find out trans- 
atlantic equivalents, since we cannot doubt, that such may be as- 
certained. I was delighted (after being panic-struck with some 
state geologists’ reports) to see the report of the legislative 
committee of the State of New York, (dated April 28th, 1840,) 
in which the sentiments of the committee cannot be misundet- 
a alates 
the confusion in De Beche, Bake- 
grauwacke, lime grauwacke, mountain 
t Tealled it the upper rock of lower secondary in some publications. 
