HAIL-STORMS. — PROGRESS OF DUNES. 



363 



Summit of the lowest passes above the Ocean from the 32nd to the 51st 



parallel, North Latitude. 







Feet. 





32nd Parallel . 



5,717 





35th „ .... 



7,472 





38th and 39th Parallel 



10,032 





41st and 42nd „ 



8,372 





47th and 49th „ 



6,044 





Kutanie Pass, lat. 49° 30' . 



6,000 



f Passes discovered by 



Kananaskis Pass, north of 49th par. 



5,985 1 



"I Captain Palliser's 



Vermilion Pass, lat. 51° 10 / 



4,944 § 



I Expedition.* 



Not only lias the depression in the Eocky Mountain 

 range, north of the 47th parallel of latitude, a remarkable 

 effect upon the climate of the Valley of the Forth Saskat- 

 chewan, but its bearing upon means of communication 

 between the Atlantic and Pacific slopes of the Eocky 

 Mountain ranges, is of the greatest importance. 



Hail-storms are not unfrequent during the summer 

 months in Eupert's Land, and the prairies sometimes 

 retain the records of their occurrence for many weeks. 

 On the Grand Coteau de Missouri, hail-storms are so 

 violent that the stones have been known to penetrate the 

 buffalo-skin tents of the Indians who hunt on that elevated 

 plateau. The thunder-storms of 1858 are given in the 

 annexed table. 



The progress of dunes affords a" very excellent indi- 

 cation of the direction and force of prevailing winds. 

 The Devil's Hills and the sand dunes surrounding that 

 dreary waste on the Assinniboine, in long. 99° 40' W., 

 showed a bare advancing surface towards the north-east, 

 being pushed in that direction by the prevailing south- 

 west wind. The sand dunes at the Height of Land in 

 the Qu'appelle Valley, in long. 107° W., lat. 51° N , were 

 advancing in an easterly direction ; their clean surfaces 

 were facing the east. Had they progressed under a pre- 

 vailing south-west wind, they would long since have 



* Proc. Roy. Geog, Soc. vol. iii. No. 5. 



