Appendix 311 



face of a limestone of Calciferous (Upper Cambrian) 

 age at Greenfield, Saratoga County, New York. 

 The individuals sometimes attain a diameter of two 

 feet, and are often surrounded by smaller speci- 

 mens apparently budding off from them. Like 

 Stromatoporce, they consist of concentric lamina-, but 

 these are concave upward, giving a bowl-shaped 

 form to the summits of the individuals. Prof Hall 

 describes them as " made up of irregular concentric 

 laminae of greater or less density, and of very un- 

 equal thickness. The substance between the con- 

 centric lines in well-preserved specimens is traversed 

 by numerous minute irregular canaliculi which 

 branch and anastomose without regularity. The 

 central portion of tlic masses is usual])' filled with 

 crystalline granular and Oolitic material, and many 

 specimens show the intrusion of these extraneous and 

 inorganic substances between the laminae." 



Professor Hall having kindly presented some 

 good specimens to the Peter Redpath Museum, I 

 have had sections made, and have thus been able 

 to verify his description, and to compare the struc- 

 tures with those of some of the more ancient 

 Stromatoporoid specimens in our collections, in- 

 cluding the Arch<neozoon from New Brunswick, of 



