70 
CONTRIBUTIONS TO DEVONIAN PALEONTOLOGY. 
[BULL. 244. 
the railroad on each side of the small ravine at East Bloomsburg, and 
contain the following faunuie: 
Faunule of zone 3 of Catawissa section (1453 A). 
[a, abundant; c, common; r, rare.] 
1. Zaphrentis cf. simplex (r). 
2. Cystodictya cf. bifurcata (r). 
4. Fenestella sp. (c). 
4. Stropheodonta sp. (r). 
5. Dalmanella tenuilineata (r). 
6. A try pa aspera (c). 
7. Amboccelia umbonata (a). 
8. Platyceras sp. (r). 
9. Styliola fissurella (a). 
10. Tentaculites spiculus (c). 
11. Phacops rana (c). 
12. Dalmanites boothi (r). 
13. D. cf. anchiops (r). 
The rock containing these fossils contains only a small amount of 
lime and is perhaps equally well described either as a calcareous shale 
or as a very impure argillaceous limestone. 
This bed has been called the Tully limestone by the Pennsylvania 
survey. a As it lies between typical Hamilton and Genesee beds, it 
unquestionably occupies the stratigraphical position of the Tully lime- 
stone of New York, but all of the fossils are Hamilton species, not one 
of the characteristic Tully forms appearing. This is doubtless to be 
explained by the fact that in physical characters this bed resembles 
the preceding Hamilton beds as much as or more than it resembles the 
Tully limestone of New York. The somewhat limey character of this 
bed indicates an approach toward the conditions of sedimentation pre- 
vailing in the typical Tully limestone area at the close of the Hamil- 
ton epoch, but the change from the Hamilton shale type of sediments 
was not sufficiently complete to induce the migration of the Tully 
fauna into the region, nor to drive out the Hamilton fauna, so that 
the latter continued to exist in a modified form. Although the fauna 
in this zone is a Hamilton fauna, the changed conditions of a later time 
interval are registered by the elimination of such characteristic Ham- 
ilton types as Spirifer granulosus and Spirifer pennatus, which were 
among the most abundant in the preceding zone. 
While this zone does not contain the Tully fauna, the modified 
character of the Hamilton fauna which takes its place, together with its 
stratigraphical position between typical Genesee shales and Hamilton 
beds, justify the correlation of the Pennsylvania survey. 
Prosser has shown that in eastern New York, where the Tully lime- 
stone is absent, its horizon is indicated at one localit}^ by the presence 
of Hypothyris cuboides associated with Spirifer pennatus. b In the 
same region Clarke has shown that where the Tully and Genesee 
are absent "the Hamilton fauna has perpetuated itself without inter- 
ruption." 6 
a Second Pennsylvania Geol. Survey Kept. G 7, pp. 282, 283, 287; Final Rept., vol. 2, p. 1319. 
h Fifteenth Ann. Rept. State Geol., New York, p. 185. 
c Thirteenth Ann. Rept. State Geol., New York, p. 554. 
