472 BOTANY OF LAKE HURON. 



Of tlie above, Anodus Dorianus, Seligera pusilla, Hypnum com- 

 pactum, and Cotoscopium nigratium, may more particularly be cited 

 as decidedly peculiar to this geological formation ; A. Dorianus, from 

 the Indian River, Owen Sound, not having hitherto been met with 

 in any other portion of North America. 



Gymnostomum curvirostrum and Fissidens grandifrons appear in 

 great abundance alike at Owen Sound and the cliffs of the Niagara 

 Kiver, but are not reported from any other Canadian locality. Of 

 the Liverworts apparently confined to this district and Formation, 

 may be mentioned more especially the Jungermannia cordifolia, the 

 Riccia sorora, and the Medotlieca porella. Other examples, moreover, 

 of the influence exerted on distribution by the chemical nature of the 

 habitat, could in this connection be cited, exemplifying even more 

 characteristically a similar peculiarity of range. One such example, 

 however, is deemed sufficient. 



Upon Laurentian soils and strata occur a number of species not 

 elsewhere detected in Canada, so far as our present knowledge of 

 their distribution extends. The more characteristic of these are given 

 in the following list : 



Polygonum cilinode. Aira flexuosa. 



Kalrnia augustifolia. Tricetum subspicatum. 



Lobelia Dortmanni. Aspleneum ebeueum. 



Limnantbemuni lacunosum. Woodsia Ilvensis. 



Pinus rigida. Aspidium fragrans. 



Potamogetia Claytoiiii. Grimmia leucophasa. 



P. Vaseyi. Racomitrium microcaspum. 



P. amplifolius. E.. Sudeticum. 



P. E,obbinsii. * R. Canesceus. 



P. rufescens. Hedwigia ciliata. 



Carex Hougbtonii. Dicranum Spurcum. 



C. lenticularis. Rbabdoweissia frigax. 



C. longirostris. Tricbostomum glancesens. 



Lycopodium inundatum. Fontinalis anti puretica, var. gigantea. 



Hypnum rugosum. 



Jungermannia barbata. 



From the Riviere aux Sables on the south to the Niagara escarp- 

 ment on the north, no rock exposures are met with of sufficient 

 importance to exercisd any appreciable effect upon the vegetation of 

 the region. Along the valleys of the Saugeen, Maitland, and Bay- 

 field Rivers, and upon the intervening gravel ridges, we find, with a 

 few exceptions, the u.sual woodland types of more or less general 



