80 much diversity of opinion exists on the subject. Only the class 

 under which the generic and specific names appear is mentioned, and 

 will, no doubt, prove quite sufficient for all purposes. 



There are included in the list 255 species as representing the fossil 

 fauna and flora of our rocks. This number will evidently be swollen 

 considerably by subsequent researches, as the measures are highly 

 fossiliferous and the exposures extremely numerous. 



Some species described and recorded by Billings and others, have 

 been excluded from the list because the types are lost or misplaced — 

 these it would be well to bear in mind as desiderata. 



Several neiv species of Palaeozoic Polyzoa, recently described by 

 Mr. A. H. Foord, and published by the Geological Survey, are incor- 

 porated in the list. 



The valuable catalogue of Palaeozoic FossilS by Mr. S. A. Miller, 

 of Cincinnati, Ohio, has been used to advantage. 



CHAZY FORMATION. 



Protozoa. 



Stromatocerium rugosum, Hall. 



P0L"Z0A. 



Pra.sopora Selwyni, Nicholson. 



Brachiopoda. 



Lingula Belli, Billings. 

 Orthis imperator, Billings. 

 Rhynchonella plena. Hall. 



Lamellibranchiata. 



Cyrtodonta breviuscula, Billings. 



Gasteropoda. 



Pleurotomaria pauper, Billings. 



