GRAPTOLITES OF NEW YORK, PART 1 745 



to note that the most important differences between the seqiieace of the 

 graptolites of Australia and that of the northern hemisphere, pointed out 

 by Mr Hall, are not borne out by the vertical distribution of the grapto- 

 lites observed in New York, and the Australian and New York graptolite 

 ranges agree in these cases. Didymograptus bifid us is stated to 

 die out in Australia long before P h y 1 1 o g r a p t u s t y p u s has dis- 

 appeared, but also at the Deep kill, where both continue through grapto- 

 lite bed 5, the former passes its maximum frequency long before the latter. 

 In the lowest Ordovicic rocks at Lancefield in Victoria "Clonograptus 

 fie xi lis and C. rigidus are found in association with Bryograptus, 

 while in Europe and America Byrograptus is a Cambrian form." At the 

 Deep kill we have found two species of Bryograptus, one in great number, in 

 a horizon undoubtedly still above that characterized by Clonograptus 

 flexilis and C. rigidus. Loganograptus in Australia does not appear 

 till Phyllograptus typus and closely allied species have become 

 extinct. This is probably exactly the case in the graptolite beds of New 

 York, where entire specimens of L og.an ogr a pt u s log an i have only 

 been found in the horizon with Diplograptus dentatus, though 

 detached branches found in deeper horizons have been doubtfully referred to 

 that species [see p.632], and Gurley also records the form only from the upper- 

 most Levis horizon. 



Since the exact faunules of the graptolite zones at Point Levis in 

 Canada have not been determined and Gurley [1896, p.294] for instance is 

 unable to state the range of Phyllograptus typus at that renowned 

 locality, the sequence furnished by the Deep kill section in New York is 

 at present to be considered as representing that of eastern North America. 

 The differences pointed out by Mr Hall are then perhaps more those l)etween 

 the Australian and North American graptolite fields on one hand 

 and the European on the other, or those between the Pacific and Atlantic 

 basins. 



There is no doubt that Mr Hall is right in placing the Lancefield 

 series with its Clonograptus-Bryograptus fauna at the base of the Australian 



