52 The American Geologist. July - 1905 
ilton fauna near their base"t is probably true for the region which 
he studied but is incorrect for the Potomac basin in which the 
typical outcrops of the Romney formation occur. As we have 
shown above, the Romney formation in its standard region contains 
in its lower member essentially the fauna of the Marcellus shale and 
in its upper member that of the Hamilton beds of New York. It is 
not until in the succeeding or Jennings formation that the Genesee, 
Naples or Portage, Ithaca and Chemung faunas are found. 
Probably that portion of part II. of most general interest is the 
discussion and correlation of sections in Northumberland and 
Columbia counties of central Pennsylvania which had been adopted 
as standard ones by the state survey in the interpretation of the 
geology of that part of the state. Perhaps the most important one 
is the Catawissa section on the Susquehanna river which was very 
carefully studied by Dr. Kindle in the field and the correlation re- 
viewed by professor Williams. Dr. Kindle shows that the calcar- 
eous shales in this section which were correlated with the Tully 
limestone by the Pennsylvania survey contain a Hamilton fauna, 
"not one of the characteristic Tully forms appearing." Dr. Kindle, 
however, considered that the zone "occupies the stratigraphical 
position of the Tully limestone of New York" while professor Wil- 
liams stated that it and the two subjacent zones contain "the normal 
fauna of the Hamilton formation." The writer showed in 1894 that 
the calcareous shale in Pike and Monroe counties in northeastern 
Pennsylvania, which the state survey correlated with the Tully 
limestone of New York is succeeded by some 200 feet of very fossil- 
iferous shales containing a characteristic Hamilton fauna which he 
referred to the Hamilton formation.* The investigations of Dr. 
Kindle clearly show, however, that the calcareous shales of central 
Pennsylvania correlated with the Tully limestone of New York by 
the Pennsylvania Survey occur at a higher stratigraphic horizon 
than those of northeastern Pennsylvania as was inferred and pub- 
lished by the writer in 1894.1 The succeeding 225 feet of bluish- 
black shales are correlated, on account of lithological similarity, 
with the Genesee shale and rather more than 25 feet above their 
top appears the first faunule of the Nunda (Portage) formation. 
Professor Williams states that the name Nunda formation has been 
adopted to designate what has heretofore been called the Portage 
or Nunda group. Two hundred feet above the top of the Genesee 
shale is a faunule containing Spirifer pennatus var posterus which 
is considered as the first appearance of the Ithaca fauna that then 
continues through about 1,400 feet of deposits to almost the base 
of the lowest red shales. Dr. Kindle states that no characteristic 
Chemung forms appear in these deposits and professor Williams 
concludes that "Faunally the evidence of the Chemung formation 
1lbid, p. 143. 
Bui. U. S. Geol. Surv., No. 120, pp., 71-73. 
t Ibid., p. 73. 
