156 SHIMER AND GRABAU — HAMILTON GROUP OF THEDFORD 



2. Encrinal limestone, coarsely crystalline, heavy-bedded, and consisting 



largely of crinoidal fragments mingled with coral sand. It is divis- 

 ible as follows : 



c. Compact crystalline crinoidal limestone, with Spirifer sculptilis, 



Favosites, Leptostrophia perplana, etc 1 J feet 



b. Black shale, with Leiorhynchus i foot 



a. Crinoidal limestone like (c) i foot 



2 feet 

 This limestone forms a small fall at the foot of the larger fall which is 

 caused by the upper calcareous beds. 



1. Blue shales, apparently non-fossiliferous ; thickness exposed, about. . . 20 feet 

 Total exposure of rock, nearly 70 feet 



In a few fragments from the lower part of the upper beds (9) the fol- 

 lowing fossils were found : 



3. Phacops rana Green. 138. Streblotrypa hamiltonense (Nichol- 

 8. Primitiopsis punctulif era (Hall). son). 



105. Spirifer mucronatus var. thedfordensis Crinoid joints. 



S. and G. 206. Ceratopora intermedia (Nich.) 



The following species were obtained from bed 5 : 



3. Phacops rana Green. 61. ? Stropheodonta demissa (Conrad). 



4. Cryphxus boothi Green. 



In the calcareous bed number 4 the following species were found : 



3. Phacops rana Green. 65. Leptostrophia perplana (Conrad) . 



4. Cryphxus boothi Green. 71. Chonetes lepida Hall. 



8. Primitiopsis punctulif era Hall. 75. Chonetes vicinus (Castelneau). 



21. Styliolina fissurella (Hall). 88. Leiorhynchus huronensis Nicholson. 



41. Pterinea flabellum (Conrad). 105. Spirifer mucronatus, thedfordensis S. 



47. Nucidites triqueter Conrad. and G. 

 Orthothetes sp. 



The following species were found loose at Rock glen and belong to the 

 beds above the Encrinal : 



9. Rhipidomella penelope Hall. 88. Leiorhynchus huronensis Nicholson. 



In addition to these, the common corals of the coral layer were found 

 with Heliophyllum halli E. and H. and Cystiphyllum vesiculosum Goldfuss 

 predominating. 



The following species were found in the Encrinal limestone at Rock 

 glen: 



