378 The American Geologist. June, 1901. 
literature in a recent publication by the New York State Mus- 
eum.* He also acids many new facts relating to the geograph- 
ic and stratigraphic distribution of the^fossils. He concludes 
that the Norman's Kill series of shales represents the most im- 
portant part of the Hudson River series, but that its fauna is 
only one of four faunas which are embraced in the Hudson 
River rocks, and the lowest of the four. He also finds that 
the Norman's kill shales are in the Trenton, lying immediately 
on the lower Trenton limestone. His summary conclusion is as 
follows : X. II. w. 
"This paper ])urports to demonstrate the presence of four 
zones of shales- in the 'Hudson River shales' of the Hudson 
vallev region about Albany. These zones, which extend from 
N. X. E to S. S. W., consist, going from west to east, of shales 
containing the Lorraine, Utica, Middle Trenton and Norman's 
kill graptolite faunas. The shales last named include lower 
Trenton conglomerate and rest on lower Trenton limestone. 
This succession of zones places the Norman's kill graptolite 
beds, which form the mass of the Hudson River .shales in the 
Hudson river valley, between the middle and lower Trenton, 
and determines, together with other facts, the Lower Trenton 
age of these shales. 
"The beds lie conformably inverted, on account of their be- 
ing the remnant of the underturned wing of an overturned fold 
of the Appalachian type. This fold has turned into an over- 
thrust fault which brought the Cambric beds as the next suc- 
ceeding terrane above the Norman's kill shales. 
"On account of the fact that the mass of the beds hitherto 
called Hudson River shales and correlated with the Lorraine 
beds of central New York, is composed (^f terranes ranging 
from the Lorraine to the lower Trenton, and on account of a 
lack of a fully representative fauna and of a complete section 
of the Lorraine portion of these terranes, it is proposed to drop 
the term Hudson River shales for the uppermost part of the 
Lower Siluric, and the term Hudson River group for the Utica 
and Lorraine l)eds, and to employ the term Norman's Kill 
shales for the clastic facies of a part of the lower Trenton 
which is characterized by the graptolite fauna of the Norman's 
kill." '_ 
♦The Hudson River beds near Albanv and their Taxonomic equivalents, 
Bull. No. 4^2, vol. viii, April, 1901. 
