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i, 2, 3 an d 4- Lockport dolomite and chert.— While 

 certain differences in the fossil content of these beds are 

 to be observed, the general fauna is much the same through- 

 out. Numerous Lithistid sponges occur in the chert beds, 

 of which the more common are: 



Actylospongia praemorsa Goldfuss. 



Aulocopina granti Billings. 

 Dendroid Graptolites are very characteristic and 

 numerous: Bassler recognizes n genera and 52 species. 

 Common species are: — 



Acanthograptus granti Spencer 



Calyptograptus cyathiformis Spencer 



Dictyonema crassibasale Gurley 



Dictyonema retiforme Hall 



Inocaulus plumosus Hall 

 Brachiopods are abundant and are represented by the 

 following species: — 



Atrypa reticularis {Linn.) 



Camarotcechia neglecta {Hall) 



Crania siluriana Hall. 



Dalmanella elegantula {Dolman) 



Delthyris sulcata {Hisinger) 



Ditcyonella corallifera Hall 



Dictyonella reticulata Hall 



Leptaena rhomboidalis {Wilckens) 



Lingulops granti Hall and Clarke 



Pholidops squamiformis Hall 



Plectambonites transversalis {Wahlenberg) 



Rhipidomella hybrida {Sowerby) 



Schizotreta tenuilamellata {Hall) 



Schuchertella subplana {Conrad) 



Spirifer niagarensis {Conrad) 



Stropheodonta profunda Hall 



Strophonella patenta {Hall) 



Strophonella cf. striata Hall 



The Bryozoa in these beds are not well preserved and 

 are difficult of recognition. The common species follow: — - 



Ceramopora imbricata Hall 

 Ceramoporella irregularis {Whitfield) 

 Drymotrypa diffusa {Hall) 

 Fenestella elegans Hall 

 Semicoscinium tenuiceps {Hall) 



