trosser.] CONCLUSIONS. ( i 
The problem of the separation of the Chemung and Gatskill was 
presented in an admirable manner by Prof. Stevenson, in his address 
before Section E of the American Association for the Advancement 
of Science, at its Washington meeting. 1 The Delaware River section 
was considered, and the professor proposed to draw the line separating 
the Chemung from the Gatskill, between the Montrose red shale and 
the Montrose sandstone, 3 and lie says, a A remarkable feature of the 
Chemung is the nonfossiliferous area of southeastern New York and 
the adjacent portion of Pennsylvania. 7 ' 3 Furthermore, "The area in 
which the lifeless portion of the column reaches much below the hori- 
zon of the Lackawaxen conglomerate embraces parts of Carbon, 
Monroe, Pike, and Wayne Counties, of Pennsylvania, and Sullivan, 
Delaware, and Greene Counties, of New York, contains rather more 
than 4,000 square miles, while the whole area under consideration is 
more than 30,000 square miles. To explain the absence of life is not 
easy; it can not be due merely to an agent which caused the redness 
or greenness of the beds, for in Huntingdon and Fulton Counties, of 
Pennsylvania, the Montrose shales have many fossiliferous beds, though 
having also many green and red beds. Besides, the Delaware section 
shows a great thickness of beds of other colors, which are equally 
without animal remains.'" 4 
The writer did not find sufficient evidence to justify an attempt to 
indicate any sharp line between the Portage and Chemung and 
Chemung and Catskill stages of this region. In the Delaware flags 
Orthonota ( l)parvula Hall was found, while still higher, near the transi- 
tion from the Montrose shales to the Honesdale sandstones, JSpirifera 
rnesastrialis Hall and Leda diversa Hall ( ?) occur. The fossils seem to 
indicate that these rocks are not younger than the Lower Chemung; and 
in fact the geologist who has latterly given the Chemung-Catskill 
problem the most careful study remarked, on seeing the specimens, 
u This fauna is not as high as the Chemung, which would be character- 
ized by Spirifera disjuneta Sow." It will be noticed that this interpre- 
tation of the section agrees more nearly with the correlation of Prof. 
Stevenson than with that indicated by the other Pennsylvania geologists 
for eastern Pennsylvania. It is probable that, beginning with the 
greenish shales and sandstones of the Starucca and the New Milford 
red shales, there is a series of deposits equivalent to the Oneonta sand- 
stone of New York, which, as is well known, gradually passes into beds 
of typical Middle and Upper Portage in central New York. 
The correlation of the Devonian system of eastern Pennsylvania, as- 
indicated above, may be shown in the following table : 
' " The Chemung and Catskill (Upper Devonian) on the eastern side of the Appalachian Basin," 
Proc. Am. Asso. Adv. Sci., vol. 40. 1892, p. 219. See an additional paper by Prof. Stevenson, in Am. 
Jour. Sci., 3dser., Vol. XL VI, p. 330. 
2 Loe. cit., p. 227. 
3 Loc. cit., p. 240. 
4 Loc. cit., p. 241. 
