180 I'he American Geologise. February, i897 
On the map of Mr. Hall those two divisions cover vast sur- 
faces in the most eastern parts of New York, entering the 
state of Massachusetts and extending northward through the 
state of Vermont. 
In order not to embarrass the reader with too many techni- 
cal and geographical details, we can say, that in the main, the 
new geological map of New York concedes to the Taconic of 
Dr. Emmons about one-third of the surface occupied by that 
stratigraphic system. The two other thirds are regarded by 
Mr. Hall and his assistants as belonging to the Silurian, call- 
ing, when it suits them, the strata "metamorphic" Calciferous, 
Trenton, Hudson, and even Oneida (the last under the name 
of Rensselaer grits). Why the name "Metamorphic" is used, 
there is no explanation, and if we consult the works published 
by members of the United States Geological Survej^ on the 
Rensselaer grits jolateau, the Green mountains of Massachu- 
setts, etc., we do not see an}^ trace of metamorphism among 
all the strata there; and, as farther north, in Vermont and in 
Canada, no metamorphism exists also, we have no explanation 
whatever of what is meant by "metamorphic Calciferous, 
Trenton, Utica, and Hudson.'" But supposing that the strata 
under discussion are metamorphic, that does not imply the 
apparition of completely different faunas, of thickness ten 
and even twenty times greater, of slates instead of limestones. 
Metamorphism, no more than invisible faults or invisible bar- 
riers, can not be of any use to explain the existence of five 
thousand and more feet of strata at Quebec city, Pointe Levis, 
Phillipsburgh, Highgate, Swanton, Shoreham, Troy, Stock- 
bridge, etc., etc., with their numerous fossils, almost totally 
different, — with only an exception of ten or a dozen forms — 
from those found in tlie typical and classic Calciferous, Tren- 
ton, Utica and Lorraine (Hudson). A misuse of palaeontology 
against the rules advocated by Alexandre Brongniart, Edward 
Forbes, Thomas Huxley, and others, cannot change the age of 
strata. The Upper, the Middle, and Lower Taconic, with a thick- 
ness of 25,000 or 30,000 feet of strata, not metamorphic, con- 
taining at different levels, several faunas most characteristic 
and quite rich in number and forms, exist in eastern North 
America; and the sooner the different organizations of otticial 
surveys accept the plain facts, as they are in the field, the bet- 
ter for the practical geology of the western hemisphere. 
