Butters: plant distribution in the Selkirk mountains 315 



questions of the distribution and relative frequency of various 

 species. 



The two series of moraines in question are the right and left 

 lateral moraines of the Sir Sandford glacier and the left lateral 

 moraine of the tributary Silvertip glacier which merges with the 

 left Sandford moraine. The region studied is that shown in the 

 accompanying map, and lies between the altitudes of about 5,300 

 feet ( 1,600 m.) and 6,500 feet (2,000 m.) . No attempt was made to 

 include the moraines lying west of the Silvertip glacier, as they are 

 still actively moving, and bear scarcely any vegetation. The moraines 



Sccle 0^ Pttt 



%. 





'"■'i^^J^vR:-, 









1 \ 



m 



mm 



Map of Tongue of Sir Sandford Glacier, showing position of Moraines. After maps by 



Howard Palmer. 



throughout this region are typical recent moraines, and it seems 

 probable that little if any of the region studied has had its present 

 form for more than three hundred years. This appears to be the 

 approximate age of the most stable portions next to the bounding 

 mountain sides. Extensive portions of the moraines have been 

 stable for 30 to 100 years, while the inner parts are progressively 

 younger, down to the "new" moraine which still rests on the edge 

 of the ice, and is of course constantlv shifting- and unstable. 



