38 THE CANADIAN NATURALIST. [Vol. vii. 



2. At the Mh of the AshSeld River, about a quarter of a 

 mile from its mouth, occur thin beds of calcareous sandstones, 

 interlaminated with silicious limestones, containing but scanty 

 traces of animal life; the only species identified being Sj^irifera 

 bimesialis (Billings). These fossiliferous beds immediately 

 overlie the apparently unfossiliferous Tentaculite limestone, 

 which, about two miles to the south-cast, crops out only a few 

 inches above the waters of the Lake. 



3. Where the boundary line between Ashfield and Colborne 

 strikes the Lake, near Port Albert, there is a cliffy outcrop facing 

 the water, of a few feet in thickness, which is observed at inter- 

 vals along the shore for about a mile. The rocks here exposed 

 are entirely destitute of fossils, and consist of the following suc- 

 cession of beds : — 



1. Yellow doiomitic limestone. 2. Thin beds of limestone 

 filled with chert. 3. Dark grey sandstones more or less bitumi- 

 nous. 4. Thin limestones, with numerous crystals of calcite. 



The lithological character of this outcrop at once indicates the 

 existence of the Tentaculite limestone or Water-lime group. 

 This formation is here found to rest directly upon the Salina 

 shales and limestones, and to immediately underlie the Cornifer- 

 ous formation, the intermediate portions of the Lower Helder- 

 berg group being apparently u'lJ'epresented. In Western New 

 York, and in some other localities in Ontario, where strata of 

 this division are observed, a few fossils occur. The more charac- 

 teristic forms met with are Leperditia alta, TentacuUtes ornatus, 

 and Eurypterus remipes (DeKay) — the latter crustacean form 

 having been also discovered, according to Keyserling, in the 

 Upper Silurian limestones of the island of Oesel in Russia. 



4. About half a mile from the town of Goderich, on the banks 

 of the Maitland, beds of yellowish calcareous sandstone, and 

 dark grey doiomitic limestones, holding lenticular crystals of 

 calc-spar, are exposed for a considerable distance along the river 

 margin. They belong to the Water-lime group, and are entirely 

 destitute of fossils. 



5. Ascending the river for nearly five miles, strata of yellowish 

 limestone interlaminated with grey slaty limestone in thin layers 

 are observed. They belong to the Corniferous formation, which, 

 a few miles to the S. E., attains a total thickness of 200 feet, 

 as shewn by the recent borings for salt. The absence of this 

 formation a few miles to tlie westward where the Tentaculite 



