33 Ithaca Group 33 



PART III. 



List of Species Occurring in the Potrage and Ithaca 



Groups. 



The present list contains all of the species which have been 

 found by the writer or reported by other from these faunas at 

 Ithaca, together with notes on their range, abundance and varia- 

 tion. 



Coelenterata. 



Cladochonus sp. 



An undetermined species of this genus is one of the most 

 abundant and characteristic fossils of the lower Portage. 



Aulopora sp. 



A species of Aulopora attached to the valves of brachiopods 

 is common at many localities in the Ithaca group and in the 

 upper Spirifer Icevis zone of the Portage. 



Stroviatopora sp. 



This genus has been reported by Prof. Williams from the 

 Ithaca group. 



Sti&opora meeki Nicholson. 



A very abundant fossil throughout the Ithaca group. 



Zaphrentis simplex? Hall. 



Specimens resembling this species have been found at a sin- 

 gle locality in a calcareous sandstone in Williams Creek secftion. 



Callopora sp. 



I have found an undetermined species of this genus occurring 

 abundantly in a calcareous stratum at station 10-5. 



Bchinodermata. 



Taxocrinus ithacensis H. S. W. 



A single perfecft specimen from the Ithaca group at station 

 7-10 has been found. 



Arthroacantha ithacensis H. S. W. 



This crinoid is rather common at station 1-13 in the upper 



