1 1 



Bryozoa: — • 



Heterotrypa frondosa, D'Orbigny. 



Heterotrypa inflecta, Ulr. 



Monotrypa undulala hemisphericd, James. 



Amplexopora discoidea, Nicholson. 



Bythopora delicatula, Nich. 



Leptotrypa irregularis, Ulr. 



Arthropora schafferi, Ulr. 



Peronopora vera, Ulr. 



Spatiopora cf. maculosa, Ulr. 



Atactopora maculata, Ulr. 



Dekayella ulrichi, Nich. 



Bythopora arctipora, Nich. 



Aspidopora, sp. 



Paleschara beani, James. 



Chiloporella, sp. 



Callopora subplana, Ulr. 



Callopora dalei, M-E and H. 



Bythopora gracilis, Nich. 



Hemiphragma whitfieldi, James. 

 Trilobites : — • 



Isotelus ma.vimus, Locke. 



Calymene caUicephala, Green. 



Trinucleus concentriciis, Eaton. 



PLEISTOCENE BEDS. 



The surface of the shale beneath the city had a high 

 relief before the first Pleistocene ice sheet moved down upon 

 it. A wide valley had been carved 200 feet below the 

 general level by a great river which flowed south from the 

 present Georgian bay region, the Laurentian river of Dr. 

 Spencer. Probably a thick layer of preglacial weathered 

 material once covered the surface, as the region is sup- 

 posed to have been dry land since Palaeozoic times, but this 

 was completely swept away, perhaps by the advancing ice, 

 leaving no record between the Ordovician and the end of 

 the Pliocene. 



Immediately upon the ancient marine shale one finds 

 a sheet of boulder clay formed by land ice ; and succeeding 

 it in some places there are four other till sheets, each separ- 

 ated from the one below by interglacial beds of stratified 



