230 TWENTIETH REPORT ON THE STATE CABINET. 



species may form several genera, belonging perhaps to different orders. 

 The species described and enumerated by this author are indicated under 

 the names G. sedgwicki, G. distans, G tenuis^ Portlock ; G. convolutus, 

 G. Sagittarius, G. pristis and G. foliiwi, Hisinger ; G. scalaris, Lin- 

 N^tjs, G. foliaceus, Lonsdale {Geol. Rep. on Londonderry, Tyrone, and 

 Fermanagh, pp. 317-321, pis. xix and xx). The species described by 

 this author as Gorgonia, probably belong to Dictyonema. 



1843. W. W. Mather and E. Emmons recognized Graptolites denta- 

 tus as characterizing the Utica slate {Geol. Rep. \st Dist. N. Y., p 390, 

 arid Geol. 2?id Dist. N. Y., p. 279). 



1843. J. Hall described Graptolithus clintoneiisis from the shales of 

 the Clinton group in the Upper Silurian formation {Geol. Rep. ^th Dist. N, 

 Y., p. 72, fig. 12). 



1845. Sir R. I. Murchison, DeVerneuil, and Count Keyserling 

 enumerated G. Sagittarius, Hisinger, and G. distichus, Eichwald, as 

 characterizing the Silurian formation of Russia {Geol. of Russia and the 

 Ural Mts., Vol. ii, p. 382). 



1846. Prof. Geinitz repeats the opinion expressed by himself in 1842, 

 regarding the nature of the graptolites ; and divides them into two sec- 

 tions, the straight and the spiral forms. In the first section he describes 

 four species : 1. G. foliaceus, Murchison (with which he identifies G. 

 pristis and G. folium, Hisinger, and G. dentatus, Yanuxem) ; 2. G. 

 priodon, Bronn (under which he includes G. ludensis, Murchison, and 

 G. teretiusculus, Hisinger) ; 3. G. Sagittarius and G. scalaris, Linn^us 

 (which he regards as varieties of the same species), Fucoides serra, Brong- 

 NiART,and G. murchisoni. Beck; 4. G. serratus,'^Q,m,OTB.^nii {Grundriss 

 der Versteinerungen, p. 310, pi. x). 



1846. E. Emmons published Fucoides simplex \== Graptolithus seca- 

 linus], from the roofing-slates of Hoosic {Natural History of New-Yorh, 

 Agriculture, Vol. i, pi. xvii fig. 1). 



1847. J. Hall described and figured fifteen species of graptolites, 

 mostly new, from the Lower Silurian strata, placing them among zoophytes 

 {Pal. N. York, Vol. i, p. 265, pis. Ixxiii and Ixxiv). 



1848. Rev. Prof. Sedgwick announced the occurrence of Graptolithus 

 Sagittarius, Hisinger, and G. latus, M'CoY in the Skiddaw slates 

 {Quarterly Jour. Geol. Soc, Vol. iv., p. 223). 



1848. J. W. Salter, described G. folium, G. pristis, Hisinger, G. 

 pristis, YSiY. foliaceus, Portlock, G. ramosus. Hall, G.tcenia, Sowerby 

 and Salter, G. tenuis, Portlock, and G. sextans. Hall, from the slates 

 of Loch Ryan, etc. {Quart. Jour. Geol. Soc, Vol. v, pp. 15-17). 



1848. Prof. Phillips enumerated the G. ludensis, G. murchisoni, and 

 three other species in the Builth, Llandeilo, and Haverford-west districts 

 {Memoirs of Geol. Survey, Vol. ii, part 1, p. 308). 



1849. James Nicol enumerated and described Graptolithus griestonen- 

 sis, G. convolutus, G. ludensis, and G. laxus {Quarterly Jour. Geol. Soc, 

 Vol. vi, pp. 63 and 64). 



