Geological position of the Catskill group. — JProsser. 365 
specimens of Spirifera granvlifera Hall, & medial is Hall,* 
Chonetes coronata (Con.) Hall, and other characteristic Hamilton 
species ; above this the blue nagging stone ; then blue and gray, 
with an occasional layer of red to Palenville, at the entrance of 
the Kaaterskill Clove ; in the Clove layers of reds alternating with 
grays predominate, but also some of blue and green occur, and 
in the lower portion of the glen are the fish beds of Sherwood ;f 
then massive conglomerates alternating with grays and reds ; and 
finally, forming the upper part of Round Top, principally coarse 
gray sandstones, which Hall and Ashburner called Pocono. + Near 
the foot of the Cascades below Haines' falls, and about four 
hundred feet below the base of the heavy conglomerate, so well 
exposed in Twilight park, in one of the bluish-gray arenaceous 
layers, are numerous specimens of Psilophyton princeps Dn. § 
This horizon is several hundred feet above the top of Sherwood's 
fish beds and consequently would be in the midst of undoubted 
Catskill as defined hx professor Hall. 1 In this great thickness of 
rocks 2 careful search failed to reveal any fossils, except the fish 
*Prof. Davis in 1883 stated that "Spirifer mueronabus and medio lis 
are both of common occurrence" at this locality (Bull. Mus. Comp. 
Zoology, Harvard College, Geol. Ser., Vol. I, p. 318). 
fProc. Am. Phil. Soc, Vol. XVII, 1878, p. 346. In connection with 
this section see Ashburner's interpretation in 2d Geol. Surv. Penn'a. F, 
1S78, pp. 218, 219, and Prof. Hall's account in the 28th Rep"t. X. Y. 
State Mas. Nat. Hist. 1879, pp. 14, 15. 
tProf. Hall in Proc. Am. As. Adv. Sci., Vol. XXIV, 1876, p. 83, and 
28th Ptep't. X. Y. State Mus. Xat. Hist., p. 15; Ashburner in 2d Geol. 
Surv. Penn'a. F, pp. 218, 219. 
fin order to remove any doubts as to the correctness of this identifi- 
cation specimens were submitted to Sir William Dawson, who wrote me 
March 19th, 1891, as follows : "So far as I can make out, most of the 
plants are Psilophyton princeps. One seems to have sporocarps at- 
tached, and the broader stems are, I suppose, rhizomata. . . . 
As to the age of your specimens, — though Psilophyton occurs in the 
Upper Devonian, I have not found beds so exclusively filled with it as 
yours seem to be, except in the middle or lower division. Perhaps it 
held out longer further south, like some other plants." 
1 See Proc. Am. As. Adv. Sci., Vol. XXIV, 1876, p. 83, where Prof. 
Hall stated that "The occurrence of this fossil [Cypricardites catskill- 
■ nsis] may, in my opinion, be relied on as characterizing the base of the 
Catskill formation, while the Holoptychiu* marks the beds above, but 
still is not known above the middle of the formation. " While in L879 
Prof. Hall in describing this particular section said "On the eastern 
face of the Catskills, in the gorge known as the Clove, the same beds 
[Catskill] have been recognized charged with the remains of Holopty- 
chius, similar to those of the beds near Blossburgh, Pa., and elsewhere" 
(28th Rep't, X. Y. State Mus. Xat. Hist., p. 14.) 
-'Sherwood's measured section from Palenville to the summil of B 
Top is 3,482' (Proc. Am. Phil. Soc., Vol. XVII. pp. 346, 347); while 
Prof. Hall in discussing it said "The section measured from Palenville, 
