BRITISH GRAPTOLTTES. 



1873. 



Nicholson, 

 ' On some Fossils from 

 the Quebec Group of 



Point Levis." 

 ' Ann. and Mag. Nat. 

 Hist.,' ser. 4, vol. xi. 



In 1873 Nicholson described some new Graptolite species 

 collected by himself from the shales of Point Levis, viz., 

 Dictyonema grandis, Tetragraptus approximatus. In this 

 paper the generic name Clonograptus (for such forms as Gr. 

 flexilis and Gr. rigidus) was first used. This name was given 

 by Hall at Nicholson's request. The three genera Clono- 

 graptus, Loganograptus and Dichogvaptus are clearly defined 

 and distinguished. 



Nicholson had by no means given up his idea of the ovarian character of the small 

 capsules found in conjunction with certain species of Monograptus, and in this paper 

 he names them, for the sake of convenience, Dawsonia. Of these he considers 

 there are four distinct species : D. acuminata, D. rotunda, D, tenuistriata, 

 1). campanulata. 



Fresh light was thrown on the structure of the genus 

 Dictyonema by Dames in 1873. In the majority of his observa- 

 tions he agrees with Hall, and he considers that there is no doubt 

 as to its graptolitic nature. In some well-preserved specimens 

 from the Silurian Limestones in Prussia, the cross threads 

 have broken, thus setting free the branches, and the character- 

 istic graptolite cells with long threads coming from their 

 apertures are easily recognisable. Such specimens demon- 

 strate that the cells are in one row only, not in alternating rows on hoili sides 

 as Nicholson had stated. 



Dames suggests that Dictyonema is allied most nearly to Dichograptus and 

 Vendrograptus, the branches of which are spread out and are not united by 

 cross threads. 



In 1873 Staclie recorded and gave brief descriptions of 

 some species of Graptolites from Osternig in Carinthia. These 

 include Diplograpsus folium, D. pristis, Graptolithus (Monograp- 

 sus) proteus, G. triangulatus, G. millepeda, G. Nilssoni, Bastrites, 

 sp. Eetiolites, cfr. Geinitzianus. From these fossils he concludes 

 that the beds correspond to the Silurian Strata of the Fichtelge- 

 birgeandtheThuringian-Saxon S chief ergebirge, and also to the 

 base of Barrande's Stage B.,and the Coniston Flags of England. 



1873. 



Dames, 



' Beitrag zur Kenntniss 



cler G-attung 



Dictyonema, Hall," 



' Zeit. d. deutsch. geol. 



Gesell.' bd. 25. 



1873. 



Staclie, 



" Die Graptolitlien- 



schiefer am Osternig- 



Berge in Kiirnten," etc., 



' Jalirb. der. k. 1c. 



geol. Eeichsanstalt,' 



bd. 23. 



1873. 



bhihnann, 



" Graptolith delvis 



omsluten af en svafvel- 



kisboll," ' Geol. F6ren. 



i Stockh. Forb.' bd. 1 , 



no, 11. 



Erdmann figured a Graptolite which he refers to Gr 

 Sagittarius, partly enclosed in a nodule of iron pyrites. 



