10 



to Elora. The upper part shows a bright red layer, rich 

 in Helopora fragilis, beneath which lie grey shales with 

 an increasing number of thin calcareous bands towards 

 the bottom. The fossils of the shale are essentially the 

 same as those in the underlying limestones, but differences 

 in relative abundance are quite marked in the case of certain 

 species. 



3. The limestone portion of the formation is well 

 shown along the disused road from Cataract Junction to 

 Credit Forks. This member consists mostly of thin-bedded 

 limestones, but it also contains many bands of interbedded 

 shale. A narrow but persistent layer of shale, about 15 

 feet (4' 5 m.) above the base of the formation, contains a 

 characteristic species of Whitfieldella. Most of the fossils 

 of the formation are common to both the shale and the 

 limestone, but there is a difference in the abundance of 

 some species, for example, Helopora fragilis is much more 

 common in the shale. The following species occur most 

 frequently: — 



Hydrozoa — 



Clathrodictyon vesiculosum Nicholson. 

 Corals — 



Favosites niagarensis Hall. 



Zaphrentis bilateralis Hall. 

 Bryozoa — 



Callopora magnopora Foerste. 



Helopora fragilis Hall. 



Homotrypa confiuens Foerste. 



Pachydictya crassa {Hall). 



Phaenopora explanata Hall. 



Phaenopora ensiformis Hall. 



Phaenopora punctata Nicholson and Hinde. 



Phylloporina angulata Hall. 



Rhinopora verrucosa Hall. 

 Brachiopoda — 



Anoplotheca planoconvexa (Hall). 



Atrypa cf. marginalis (Dalman). 



Atrypa reticularis (Linnceus), (rare and doubtful). 



Atrypa sp. nov. (numerous and typical). 



Camarotoechia neglecta (Hall). 



Dalmanella elegantula (Dalman). 



Hebertella fausta Foerste. 



