104 



3 — This limestone is referred to as the 'encrinal 

 limestone.' Some of the common fossils are: — 



Craspedophyllum archiaci (Billings) 

 Favosites turbinata Billings 

 Leiorhynchus laura (Billings) 



4 — This shale possesses a rich coral fauna with Helio- 

 phyllum and Cystiphyllum predominating. The more 

 common fossils are: — ■ 



Corals — 



Alveolites goldfussi Billings 



Cladopora frondosa (Nicholson) 



Cyathophyllum conatum Hall 



Cystiphyllum vesiculosum (Goldfuss) 



Favosites billingsi Rominger 



Favosites placenta Rominger 



Heliophyllum halli E. and H. 



Phillipsastrea verneuili E. and H. 



Striatopora linnaeana Billings 



Zaphrentis prolifica Billings 

 Bryozoans — 



Fenestella arkonensis Whiteaves 

 Brachiopods — 



Athyris fultonensis (Swallow) 



Camarotoechia thedfordensis Whiteaves 



Chonetes lepida Hall 



Cyrtina hamiltonensis Hall 



Pholidostrophia iowaensis (Owen) 



Rhipidomella penelope (Hall.) 



Spirifer mucronatus thedfordensis Shimer and Grabau 

 Worms — 



Spirorbis omphalodes (Goldfuss) Nicholson 

 Gastropods — 



Platyceras subspinosum Hall 

 Trilobites — 



Phacops rana (Green) 

 5 — The shales and argillaceous limestones of this 

 member contain comparatively few fossils. Spirifer mu- 

 cronatus thedfordensis S. and G., occurs, increasing in 

 abundance towards the top. Chonetes lepida Hall, 

 C. vicina (Castlenau), Pterinea flabellum (Conrad), Pha- 

 cops rana (Green), Cryphaeus boothii (Green), occur 

 in the lower beds. 



