386 G. II. Girty — Fauna found in the Devonian 



evidence here available indicates at least that the base of the 

 formation in this region probably belongs to the Genesee 

 period. The peculiar punctate Lingnla which I have called L. 

 Williamsana occurs in the typical Genesee, but is not known 

 to me elsewhere,'* and Leiorhynchus quadricostatum also is a 

 Genesee species. Meristella Haskinsi was described from 

 rocks of the Hamilton period, but my identification, owing 

 partly to insufficient material, is only qualified. Plethospira 

 socialis, while it has its closest allies in the early Devonian, is 

 nevertheless probably a new species with little weight as evi- 

 dence, and Prioniodus armatus together with Sjjorangites 

 Huronensis? , which I believe to be correctly identified, are of 

 supposedly Genesee age. On the whole, it is safe to say that 

 the base of the Devonian black shale at these points was about 

 contemporaneous with the middle Devonian of New York, and 

 can probably be correlated with the Genesee shale of that 

 State. 



Genesee shale of New Albany, Indiana," clearly accepting Meek's correlation 

 above referred to. while Hall and Clarke (Geol.Surv. New York, Pal., vol. viii, pt. 

 1. desc. pi. 4K, fig. 6) cite Lingula sp. (L. Williamsana of this paper) occurring in 

 the black shale at Yanceburg, Kentucky, as from the Genesee horizon." These 

 instances are enough, though others might be cited, to support the statement that 

 the tendency among recent workers has been to concede the correlation of the 

 black shale of the Central States with the Genesee shale of New York. And as 

 a general statement this seems to be correct, especially when referring to the 

 basal portion of the formation, and where, as is the case in a considerable portion 

 of the region named, it rests upon strata of recognized Hamilton age. However, 

 Newberry (1. c.) speaks of finding Portage fossils in the upper part of the Huron 

 shale in Ohio (Clymenia? complanata, Chonetes speciosa, Orthoceras aciculum, 

 Leiorhynchus quadricostatum. The last named species is characteristically 

 Genesee, and I am at a loss to know what form is indicated by Chonetes ? speciosa.) 

 Williams states (this Journal, vol. iii, 1897, p. 398) that at Irvine, Kentucky, the 

 black shale conditions continued well up into Carboniferous time, while in the 

 vicinity of Big Stone Gap he finds the black shale resting upon a limestone full 

 of Comiferous corals, from which he reasons that the beginning of the black 

 shales for this region can be fixed at a horizon "closely corresponding to that of 

 the Marcellus shale in the New York section." This would make the black shale 

 ranore, locally at least, or alternately, from the age of the Marcellus shale of New 

 York to at least that of the Kinderhook group of Illinois. A similar conclusion 

 has been stated by Shaler, who considers this formation in Kentucky and Tennes- 

 see to include everything from the top of the Oriskany to the Chemung (Geol. 

 Surv. Kentucky, vol. iii, n. s., 18, p. 173). Lyon, however, writing in 1859 

 (Trans. St. Louis Acad. Sci., vol. i, p. 619-620) seems inclined on paleontologic 

 evidence to refer the black shale of western Kentucky and Tennessee to the 

 Lower Carboniferous rather than the Devonian, but this 1 believe to be due to a 

 misapprehension on his part of the real position of the Goniatite beds at Rock- 

 ford, Indiana, as included in, instead of situated above, the black shale, as is in 

 fact the case. 



*In a recent letter from Prof. J. M. Clark in relation to the Lingulas of the 

 Genesee shale he speaks of observing Lingulas of elongate and slender spatulate 

 shape in the higher layers of black shale which appear after the introduction of 

 the normal Portage fauna, and adds that these black shales above the Genesee 

 horizon are ofteu confounded with true Genesee. It may be that our specimens 

 of L. Williamsana from Seneca Lake are from this horizon, i. e.. later than the 

 Genesee, but both an impunctate Lingula which I identify as L. spatulata and a 

 punctate one which seems to be L. Williamsana occur iu the Styliola layer of the 

 Genesee, so that the evidence of this species speaks for Genesee or a little later. 



