6 PALEONTOLOGY. 



furnish even a stronger argument against the conclusion that this formation 

 miffht belonof to the Carboniferous. Hence we cannot doubt that these beds 

 belong to the Devonian, and probably to about the horizon of the Hamilton 

 Group of the New York series.* Indeed, in 1860, on nearly the same evi- 

 dence, this formation, at localities a little farther north, was referred by the 

 writer to the Devonian, from the examination of specimens brought from 

 there by Colonel Simpson; though at that time this rock was not known to 

 contain silver-mines, f 



The little Proetus, illustrated by fig. 10 on plate 1, probably also came 

 from near the same horizon as the Devonian fossils mentioned above, as it 

 is contained in a similar matrix quite unlike that containing the Pinon Range 

 fossils. 



On the lower part of plate 3, a few fossils are figured together in a sepa- 

 rate division, because they are of a somewhat doubtful nature. They are 

 also from the White Pine District, and came from beds known to hold a 

 position between well-marked Carboniferous and Devonian rocks. All of 

 them, excepting the Spirifer, came from a black bituminous shale, asso- 

 ciated with some more or less arenaceous beds, beneath well marked Car- 

 boniferous limestones. The Avicidopecten (fig. 10) is very closely allied to 

 some western Carboniferous forms; and the little shell represented by fig. 8 

 also resembles Carboniferous species believed to be at least nearly related 

 to Posidonomya. The Brachiopod represented by fig. 9, however, is remark- 

 ably like Devonian species of LeiorJiyncJius, and hence would favor the 

 opinion that this shale is Devonian. The Spirifer represented by fig. 11 

 seems to belong to the common and widely-distributed Carboniferous species 

 S. cuspidatus, and came from a gray, subcrystalline, cherty limestone, above 

 the above-mentioned black slate, and was associated with some large Crinoid 

 columns, casts of an Orthis, like 0. resupinata or 0. Miclielini, and imperfect 

 specimens of a smaller Spirifer, apparently like the Devonian species S. 



* These remarks on the Devonian age of the White Pine silver-bearing rocks 

 were quoted by Mr. Arnold Hague, in the Mining Eeport of Mr. King's Survey, 416, 

 (issued in 1870.) It is to be regretted, however, that, owing to the fact thatMr. Hngue 

 did not see the proof, several annoying typographical errors, in the names of the 

 fossils mentioned, were not corrected. — F. B. M., Sept. 29, 1874. 

 t See Proceed. Acad. Nat. Sci. Philad., 1800, XII. 



