572 NEW YORK STATE MUSEUM 



mens of this long lived subclass may be of a merely local 

 character. 



On account of the radical changes in the composition of the 

 fauna and of the large break in the section between the preced- 

 ing and this zone, which, taking the average dip of the beds into 

 account, may represent 300 feet of covered rock, it might be sur- 

 mised that a number of zones must be missing between the two, 

 and the succession of the zones is incomplete in this regard. 

 Reference to the European succession of zones shows however 

 that this is hardly the case, for in the Skiddaw beds, for instance, 

 the same two zones have been found in direct succession. It is 

 true, there may exist an intermediate, transitional zone, contain- 

 ing a more balanced mixture of the two faunas, such as has been 

 found in Scania (see above, p. 569). 



All the species of this fauna, described by Hall, were cited by 

 him simply as coming from the Quebec group of Point Levis. 

 In each description, however, the association is recorded in which 

 the form was found, and from these records it becomes evident 

 that the separate existence of this peculiar assemblage of species 

 at Point Levis was well known to that illustrious observer. 

 Lapworth (loc. cit.) found no material from this zone in the col- 

 lections submitted to him, and therefore does not mention or 

 locate this horizon in his series of graptolite zones. 



Dr Gurley (loc. cit. p. 302) states that besides the fauna of the 

 Main Point Levis zone he had before him a smaller collection of 

 Point Levis shales, from a locality 1-J miles north of the east 

 railway station at Levis, which has a strikingly different fauna; 

 adding: " It was remarkable not so much for the species present 

 (though the Diplograpsidae seem highly characteristic) as for 

 those absent." His Ordovician table of graptolites (loc. cit., 

 p. 296 ff) proves that the third Deep kill fauna is identical with 

 this second Point Levis fauna. Gurley calls the latter simply 

 the " Point Levis fauna" and, together with two similar associa- 

 tions, from the Pinon range at Summit Nev., and from Arkansas, 

 refers it to the upper Calciferous zones. 



In England the zone with Diplograptus dentatus, 

 Cryptograptus antennarius and Trigono- 

 graptus ensiformis is well developed in the Ellergill 



