Dec, 1912.] Ordovician Section, Lake Huron Area. 41 



Among other forms occurring in the Cloche island limestones 

 may be mentioned Rafinesquina inquassa, Dalmanella gibbosa, 

 and Conradella obliqua, all of which suggest Black river age. 

 Streptelasma profundum, Rhynchotrema (?) ottaivaensis, Orthis tri- 

 cenaria, Dinorthis pectinella, a small Dalmanella belonging to the 

 testudinaria group, Strophomena filitexta, Plectambonites curds- 

 villensis, Leperditia fabulites , Bumastus miller i, and numerous other 

 species range from the Cloche island Black river limestones into the 

 Curds ville strata, exposed at the base of the Trenton on Goat 

 island. Solenopora compacta, HerbeteUa bellarugosa, and Actino- 

 ceras bigsbyi, hitherto not found above the Cloche island limestones, 

 may eventually be found also in the Curdsville beds on Goat 

 island, since they occur in the Trenton elsewhere. Not being famil- 

 iar with Black river faunas, the writer submitted the fossils 

 collected to Prof. Percy E. Raymond, and was pleased to receive 

 his confirmation as to the Black river age of the Cloche island 

 limestones. 



The bryozoans were submitted to Dr. E. O. Ulrich, with the 

 following results: Batostoma humile, B. varium, B. winchelli, 

 Eridotrypa mutabillis, Ilomotrypa minnesotensis, Nicholsonella 

 ponderosa, Phyllodictya frondosa, Phylloporina sublaxa, Prasopora 

 insularis are represented by varieties also occurring in the Decorah 

 shales of the Mississippi basin, and thus tend to corroborate the 

 reference of the Cloche island beds to the Black river. As a matter 

 of fact, Batostoma winchelli and Homotrypa minnesotensis were 

 identified also from the Curdsville bed in the lower part of the 

 Trenton on Goat island, and some of the other species, such as 

 Batostoma humile, Eridotrypa mntabilis, and Prasopora insularis, 

 are known to range upward into the lower Trenton, but, to Dr. 

 Ulrich, this bryozoan fauna presented a distinct Decorah shale 

 facies. Most of these bryozoans were collected in the upper part 

 of the Cloche island beds, above the SO foot level mentioned in the 

 preceding lines. Further collecting may indicate the presence 

 also of other faunas within these beds. 



5. Curdsville and other Trenton Exposures on 



Goat Island. 



The lowest exposures of the Trenton on Goat island present a 

 fauna very similar to that of the underlying part of the Black river, 

 excepting for the apparent absence of Receptaculites, Maclurea, 

 Gonioceras, and a few other fossils, and the presence of the inter- 

 esting crinoid and cystid fauna known from Curdsville, Kentucky, 

 and from Kirkfield and other Trenton localities in Ontario. 

 While a form of Dalmanella belonging to the testudinaria group, 

 and Plectambonites curdsvillensis are present in these lower Trenton 

 strata on Goat island, they occur also at various horizons in the 

 underlying Cloche island limestones. 



