566 AxxALS OK THE Carxegie Museum. 



also on Valcour Island. The zone is characterized by the great 

 abundance of cystid fragments. The characteristic fossils are : Cy- 

 hele prima, Eoharpes antiqiiatiis, LcvichodoDias lialli, Malocystites mur- 

 chisoiii, Malocystites emiiio/isi, Glyptocystites forbesi, Paleocystites tenui- 

 radiatiis, Rapliistonia stamineitiiu Mac/uritcs magnus, Plccsioviys stro- 

 phontenoides and Camerella variaus. 



Division j : Tlie Camarotachia plena Division. 



The strata of this division are rather thin-bedded, light grey, coarse- 

 grained limestones abounding in fossils. Near the base there are always 

 buff-colored, pure, fine-grained dolomites and heavy-bedded, coarse- 

 grained blue limestones. The only fossil which is found throughout 

 this division is CamarotcEchia plena. Other characteristic fossils are : 

 Camarotoechia major, Orthis igfiicula, Modiolopsis fabaformis and Gla- 

 phiiriis piistiilatus. There is, in this division, a decided falling off 

 in the number of gastropods and ])elecypods, there being only six of 

 the former and five of the latter. There are about as many trilobites, 

 sixteen, in this division as in division i, and eight of these are 

 found in all three divisions. Brachiopods, in the matter of number 

 of species, are very uniform through the section, as there are 13 

 known in each division at the present time. They dominate the 

 fauna in both the first and third divisions, but in the first division it 

 is one of the Protremata {Hebertella), while in the third division it 

 is one of the Telotremata {Camarotarhia) which is most abundant. 



There are three well-marked zones in this division : 



Zone 3a. T/ie Glaphurus pitstiilatiis zone. 



This zone is found at the base of Division 3 at Valcour Island, 

 Chazy, Cooperville, and Isle La Motte. The characteristic fossils are : 

 Glaphurus piistulatiis, Illceniis globosiis, Illczniis erastusi, Isotclus har- 

 risi, Jiemoplciiridcs canadensis, Pliomerops canadensis, Amphilichas 

 minganensis, Pseiidosphcerexochus vulcanus, Camarotoechia plena, Cono- 

 cardium bcecheri, Bitcania sulcatina, and several cephalopods. 



Zone 3b. The Camarotoechia major zone. 



This zone stands between 3a and 3c and its faunule is a transition 

 between the two. Camarotoechia becomes more abundant and better 

 developed, and the trilobites and brachiopods become fewer in species. 

 The best development is at Valcour Island. Characteristic fossils are : 

 Camarota'chia plena, Camarota'chia major, Hcbertclla vulgaris, Orthis 

 ignicuhu Malocystites emmonsi, Malocystites sp., Paleocystites sp., 



