1 8 NEW YORK STATE MUSEUM 



simply termed the Dicellograptus zone. Altogether, the fact of the great 

 difference in the faunal expressions of this and the following zone, in which 

 the biserial forms entirely dominate and the distinct presence of faunules, 

 which eventually may be recognized as subzones of the Dicellograptus 

 zone, necessitate the recognition of the latter as a separate unit. 



One of these subzones is quite obviously represented by a faunule 

 collected by the writer at the power house of the traction company, north 

 of Lansingburg. While having in common with the other outcrops 

 of Normanskill shale the species: Didymograptus serratulus, 

 Azygograptus ? simplex, Dicranograptus ramosus, 

 Climacograptus parvus, C . modestus, C . bicornis and 

 D i p 1 o g r a p t u s f o 1 i a c e u s, this faunule contains in Diplograptus 

 amplexicaulis var. p e r t e n u i s , Diplograptus euglyphus 

 var. pygmaeus, Climacograptus p u t i 1 1 u s mut. e x i m i u s 

 and Cory no ides gracilis, peculiar elements of its own. It is 

 characterized by the great prevalence of minute Diplograpti and Climaco- 

 grapti (C . modestus, C. parvus, C. putillus mut. ex i mi us) 

 and would seem to represent for this reason a transition to the next zone. 



Another peculiar association has been observed by me near Speigle- 

 town, north of Troy. It consists of 



Nemagraptus exilis var. linearis Corynoides gracilis mut. perungulatus 



Dicellograptus divaricatus var. rectus Diplograptus euglyphus 



D. intortus 



The localities mentioned in the foregoing tables are situated in the two 

 belts of Champlainic rocks which with some interruptions flank the Lower 

 Cambric slates of the slate belt of eastern New York. They lie in Colum- 

 bia, Rensselaer and Washington counties or on the east side of the Hudson 

 river, with the exception of those of Normanskill (Kenwood) and Glenmont, 

 which arc in Albany county and on the west side of the river. The zone 

 itself has not yet been mapped, with the exception of a small area in the 

 neighborhood of Albany in a former paper of the writer | iqoi ] and its car- 

 tographic fixation will, no doubt, lead to a distinction of its subzones and of 



