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Cystiphyllum americanum anderdonense, Grabau. 

 Diplophyllum integumentum, Barrett. 

 Favosites basaltica nana, Grabau. 

 Favosites concava, Grabau. 

 Favosites rectangulus, Grabau. 

 Helenterophyllum caliculo'des, Grabau. 

 Spirifer (Prosserella) lucasi, Grabau. 

 Pleurotomaria cf. velaris, Whiteaves. 



The three Silurian stromatoporoids are of very 

 doubtful identification; if these are excepted, the remaining 

 fossils have a strong Devonian rather than Silurian aspect. 

 Rev. Thomas Nattress of Amherstburg, who has studied 

 the Anderdon limestone from the stratigraphic point of 

 view, is convinced that it represents a Devonian sedi- 

 mentation in an enclosed basin. 



3. The underlying brown dolomites are not sufficiently 

 exposed to yield important stratigraphic evidence: they 

 appear to be destitute of fossils. 



A second exposure of beds belonging to this series is 

 furnished by the cut of the Livingstone canal in the 

 Detroit river. The total length of the cut is 11 miles 

 (17-7 km.), its width is 300 to 800 feet (91 to 244 m.) and 

 its depth 23 feet (7 m.). Just above Amherstburg a 

 section of the canal about a mile long was excavated 

 within a coffer dam and is hence known as the dry cut. 

 The material removed from the river bed, to an amount 

 of 800,000 cubic yards, has been piled on either side of 

 the cut and for a few years at least will be a good collecting 

 ground for Monroe fossils. 



Grabau maintains that these beds represent the upper 

 part of the Monroe formation — above the Anderdon 

 limestone, while Nattress as stoutly maintains that they 

 belong to the lower Monroe. For our present purposes 

 it will suffice to consider these beds as yielding an interesting 

 series of fossils with both a Devonian and a Silurian aspect. 



The commoner species are as follows: — 



Hydrozoa 



Clathrodxtyon ostiolatum, Nich. 

 Idiostroma nattressi, Grabau. 



35066—5! 



