5G4 NEW YORK STATE MUSEUM 



Temple (Cabri^res), making it the type of the new genus 

 Rouvilligraptiis. As this species has to the writev's knowledge 

 been found only in the St Anne beds, which are identical with 

 the Deep kill zone (Did. b i f i d u s zone) to be described next, 

 it appears that both the Tetragraptus and the D i d y m o - 

 graptus bifidus zones (St Anne beds) may be present at 

 Cabri^res. 



From the auriferous shales of Tictoria, AtistraUa, Etheridge jr^ 

 has reported the occurrence of such well known Levis 

 fossils as Tetragraptus bryonoides (=s e r r a), 

 T. q u a d r i b r a c h i a t u s , T. f r u t i c o s u s , P h y 1 1 o - 

 graptus typus, Loganograptus logani and 

 Didy mograpt us nitidus, to which McCoy2 has 

 added Goniograptus thureaui. This list indicates 

 the presence of the Tetragraptus zone in Australia. 



The preceding brief review of a number of publications 

 which announce the presence of the Tetragraptus fauna is 

 sufficient to demonstrate the vastness of the area which it 

 once occupied. Prof. Frech^ has suggested the probability that 

 there existed four grand marine provinces in the Lower Siluric 

 which w^ere more or less separated from each other, viz the 

 Bohemian-Mediterranean, the Baltic, the North Atlantic and 

 the Pacific-North American basins. The former existence and 

 extension of these provinces is deduced from the comparative 

 study of the horizontal distribution of the faunas, specially 

 of their trilobite element. The graptolites however are ex- 

 pressly excepted as passing beyond the boundaries of these 

 basins, and this phenomenon is explained by their pelagic or 

 abysmal habitat in contrast to the littoral or shallow sea habitat 

 of the provincial faunas. This necessity of contrasting the 

 graptolite faunas with the other faunas on account of their 

 vast geographic distribution, together with the well known 

 fact of their short vertical range, is a conclusive demonstra- 



' Ann. and mag. nat. hist. 1874. 4th ser. 1:41. 



» Geol. surv. Victoria. Troclr. pal. Victoria. Decade 5, 1877. p. 39. 



' Lethaea palaeozoica. 1807. 2:88 ff. 



