Tu \ NKW YD UK STATE MUSEUM 



SlMMAIiV 



Tlic \)rv\) kill siMtion lias fiirnislicd extensive eoHectioiis of 

 three different •rniptolite horizons whicli, termed after their 

 most cluiraeteristie orjjanisnis, are: 



c Zone with I> i j* 1 o ^ r a }» 1 u s d e n 1 a t u s and Crypto- 

 «r r a p t u s a n t e n n a r iju's 



h Zone with 1) i d y m o g r a p t u s b i f i d u s and P h y 1 1 o- 

 «i r a \) t 11 s a n n a 



n Zone witli Tetrajjraptns 



Two of these zones [a and h) are found in contiguous succes- 

 sion, the third is separated by a break in the exposure, but is 

 certainly superjacent on the second zone 6. In Great Britain 

 and Scandinavia, all three zones have been observed in the same 

 succession. In Canada, zone a is known from several regions, 

 the most important being the Levis and St John regions. The 

 typical fauna of zone h has become known from the beds near 

 the St Anne river in Canada, and zone c is again present in the 

 Levis beds. The succession of these zones has thus far not been 

 reported as observable in any of these Canadian regions. 



The stratif/raphij of the Deep kill section demonstrates that the 

 Mnin Point Levis heds or those of the Tetragraptus zone are the 

 loiccst of the series: that thcij arc followed htf the St Anne heds or 

 those of the zone icith D id y in o (j r a p t u s h If I d a s etc., and 

 ///(// the Point Levis hals, containing the zone with Diplograp- 

 t II s d r n t a t u s etc., overlie cither dircetly the St Anne zone or 

 arc separated from it by only an intermediate transitional zone. 



As the Levis beds have been demonstrated to belong to the 

 Beekmantown or Calciferous formation, the two lower of the 

 zones certainly rei)resent part of the gra])tolite facies of that 

 formation, while the third zone may either belong to this or to 

 the Chazy formation. 



In using the results of a fornjer investigation by the writer 

 of the sliah's in the vicinity of Albany (X. Y. state nius. Bui. 41') 

 tin- /on«*s recorded in tin* first rohniin of the following correla- 

 tion table of the ('hamj»lainic or Lower Siluric graptolite shales 

 <an be claimed to have been discerned in this region. 



