GRAPTOLITES. 61 
of the graptolites, recognizing them as true zoophytes, and indicating 
their analogy with Sertularia and Plumularia. He suggested that the 
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. folium, Hisiagee: G. scalaris, Linn., 
G.foliaceus, Lons. (Geol. Rep. on Londonderry, Tyrone, and Fermanagh, 
pp. 317-321, pls. xix and xx.) The species described by this author as 
Gorgonia, probably belong to Dictyonema. 
1843. W. W. Mather and EH. Emmons recognized Graptolithus dentatus 
as characterizing the Utica slate. (Geol. Rep. 1st Dist. N. Y., p. 390, 
and Geol. 2nd Dist. N. Y., p. 279.) 
1843. J. Hall described Graptolithus Clintonensis, from the shales of 
the Clinton group in the Upper Silurian. (Geol. Rep. 4th Dist. NV. Y., 
p- (2, fig. 12.) 
1845. Sir R. I. Murchison, De Verneuil, and Count Keyserling enu- 
merated G. sagittarius, Hisinger, and G. distichus, Hichwald, as charac- 
terizing the Silurian formations of Russia. (Geol. of Russia and the Ural 
Mts., vol. ii, p. 882.) 
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 de- 
scribes four species: 1. G. foliaceus, Murchison, (with which he identifies 
G. pristis and G. folium, Hisinger, and G. dentatus, Vanuxem); 2. G. 
priodon, Bronn, (under which he includes G. Ludensis, Murchison, and 
G. teretiusculus, Hismger); 3. G. sagittarius and G. scalaris, Linn. 
(which he regards as varieties of the same species), Hwcordes serra, Brong., 
and G. Murchisoni, Beck; 4. G. serratus, Schlot. (Grundriss der Ver- 
stein, p. 310, pl. x.) 
1846. EH. Emmons published Fucoides simplex [= Graptolithus' seca- 
linus|, from the roofing-slates of Hoosic. (Natural History of New- 
York, Agriculture, vol. i, pl. 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. NV. York, vol. i, p. 265, pls. lxxii, lxxiii, and Ixxiv.) 
1848. Rev. Prof. Sedgwick announced the occurrence of Graptolithus 
sagittarius, His., and G. latus, McCoy, in the Skiddaw slates. (Quarterly 
Jour. Geol. oe vol. iv, p. 293, ) 
1848. J. W. aie described G. folium, G. pristis, Hisinger, G. pristis, 
var. foliaceus, Portlock, G. ramosus, Hall, G. Tenia, Sowerby and Salter, 
G. tenuis, Portlock, and G. sextans, Hall, from the slates of Loch Ryan, 
etc. (Quart. Jour. Geol. Soc., vol. v, pp. 15-1T.) 
1848. Prof. Philips enumerated the G. Ludensis, G. Murchisoni, and 
