BEEKMANTOWN AND CHAZY FORMATIONS OF CHAMPLAIN BASIN 423 



As far as observation of the ectosiphuncle is possible in the type 

 specimen, it appears that the septal neck did not reach beyond the 

 preceding septum and that an endosipholining is absent, hence the 

 reference by exclusion of the genera Yaginoceras and Cameroceras, 

 to Endoceras, with some doubt. 



Endoceras magister sp. now 



Plate 8, figure 1 



Description. Very large orthoceracone with large ventral siph- 

 uncle and extremely deep cameras. The fragment here figured has 

 a length of 250 mm and attains a width of 106 mm ; its rate of 



Fig. 7 Endoceras magister sp. now Transverse section, x / 



growth is 20 mm in 100 mm. The cameras are very deep, the 

 septa in the average 22 mm apart and very concave, their concavity 

 being as large or greater than the depth of the cameras. The living 

 chamber has not been observed. The siphuncle is large, circu- 

 lar (?) in section, 1 its maximal width in the specimen 47 mm; the 

 septal necks do not extend beyond the preceding septum. The 

 surface is smooth. 



Position and locality. In the lower Chazy (B 4 of our section) 

 at the Valcour shore of New York. 



Observations. This imposing cephalopod is easily the master of 

 the rest of the Chazy species by its dimensions and specially the 

 depth of its chambers and the width of the siphuncle. No other 

 form has been described from the Chazy of either New York or 



1 The section figured [text fig. /! shows that the specimen is com- 

 pressed and the original sections of conch and siphuncle not any more 

 -ascertainable. 



