BOTANICAL INFORMATION. 203 



July morning, when great numbers are seen constantly in the 

 air, trying with all their strength to leap over the cataract ; 

 at last the creature resorts to a more quiet place, and repeats 

 his summersault; but falls unfortunately into the lurking 

 basket of the Indian, who lies on the sunny rock above, 

 watching his victim. 



Apparent geological features. — The pseudo-columnar ba- 

 saltic ranges which wall the bases of the mountains, men- 

 tioned already in the former regions, are common in these 

 districts, particularly along the sides of the plateaux. Their 

 contrasting appearance imparts a certain freshness to 

 the vegetation. A great part of the coteau of the plateau, at 

 the united Lewis, Saptona, or Snake river, contains preci- 

 pices of regular columnar basalt. 



The sterile plateaux are of a trappean formation, covered 

 either with loam or sand, containing series of rounded conic 

 piles of inconsiderable height, and in the centre lofty walls, 

 "ke perpendicular truncated masses of 1-2000 feet high. 

 This rock appears as if cast over that whole region, known as 

 the Spokan plains of the Upper Columbia. 



The naked sides of mountains or summits are mostly of 

 gray granite, which has a slight south-easterly, but often only 

 a local inclination, often finely grained and laminated on the 

 same block. Granite mountains also, in this region, maintain 

 a vegetation when they are not denuded by fires. 



Of minerals, lead occurs in conglomerate with pyrites, on 

 the c6tes of Coutennay river ; it was discovered by Chief-factor 

 Macdonald, and the spot is only known to him. Very 

 few localities in Upper Oregon present secondary rocks to 

 any extent. 



General character of the vegetation. — Eastern portion of 

 the great western region of the Conifera ! Apparent centre 

 °f the Umbellifera, Scrophularina, Asphodeli, and Rhinan- 

 therm in N. America ! The families which abound in several 

 genera are : Polemoniaceee, Boraginem* Vaccinea, Ranuncu- 



* Leyuminosa, to which add, also Caprifolia and Rhamni ! 



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