948 NEW YORK STATE MUSEUM 



It is added that in a neighboring bed there is a vast quantity 

 of debris of trilobites, which seem to agree with the graptolites 

 in indicating an Upper Cambric age, as they are apparently 

 more nearly related to the trilobitic fauna of the Potsdam of 

 Newfoundland, as described by Billings, than to that of Levis. 



Sir William Dawson's conclusion of the presence of an Upper 

 Cambric graptolite zone at the lower St Lawrence river has 

 a few years later been verified by Prof. Charles Lapworth 

 from material which had been submitted to him by the Cana- 

 dian Survey. In his report 1 Lapworth recognizes three zones 

 namely, in descending order, the Griffin point or Marsouin river 

 zone (zone of Coenograptus gracilis) which corre- 

 sponds to the Normans kill beds of New York, the Ste Anne 

 zone (zone of Phyllograptus anna) which has been 

 recognized in the middle of the three Deep kill graptolite zones, 

 reported on in a former paper, and finally the Cape Rosier 

 zone (zone ofDictyonema sociale and Bryograptus). 



It is the last zone which this year has been found fully rep- 

 resented within the slate belt of eastern New York. We quote 

 those remarks of Lapworth's on this zone, which seem important; 

 to our inquiry. 



The oldest graptolitic zone represented is the D i c t y o - 

 nema sociale zone of Barrasois river (Cape Breton 

 island) and of Cape Kosier, Gaspe. There are very few specific 

 forms occurring in this zone, but they constitute together a 

 very peculiar and distinct group, totally different from those 

 of the remaining zones. The genera include Dictyonema, 

 Bryograptus and Clonograptus, together with the dubious genus 

 Staurograptus of Emmons. The Dictyonema appears to me to be 

 absolutely identical with one of the forms referred by European 

 ( Scandinavian) geologists to Dictyonema flabel- 

 1 i f o r m e Eichwald, which is also, so far as our present evi- 

 dence enables us to judge, identical with Dictyonema 

 sociale Salter, from the Tremadoc of north Wales. 



To this zone belong the Barrasois river beds, those of Cape 

 Rosier, of Little White river, of Grand Mechin point, of half a 

 mile west of Long point, Matane, Little Capucin river, etc. 



^Preliminary Report on some Graptolites from the Lower Palaeozoic Rocks, 

 on the South side of the St Lawrence from Cape Rosier to Tartigo River, from 

 the North shore of the Island of Orleans, etc. Roy. Soc. Can. Proc. and Trans,. 

 1887. 4:167-84. 



