FLORA OF POCATELLO, IDAHO I 



By Blanchii^ H. Soth. 



pOCATELLO, Idaho, is situated almost at the mouth of the 

 •■• valley where the Port Neuf river emerges from the hills 

 on its way to the Snake. The higher hills about the town 

 are the northernmost bluffs and outposts of the Wahsatch 

 range — among the oldest elevations of land on the continent. 

 Briefly and very generally, three geological periods are re- 

 corded by (1) the mature hills west of town of which Kim- 

 port Peak is the highest point overlooking the valley, (2) the 

 nearly level benchland in front of them and a hundred feet 

 or more above the present level of the river and (3), due to 

 a comparatively recent elevation, the cutting of the face of 

 •the bench into a series of shallow gulches and a few deeper 

 narrow canyons. During the period of subsidence at the end 

 of the glacial epoch an arm of great Salt Lake drained by 

 way of Red Rock Pass through the Port Neuf valley into the 

 Snake river. At that time huge deposits, of sand, gravel and 

 clay were dumped into the valley. The lower sand hills east 

 of town are of this heterogeneous material. No doubt with 

 them were carried the roots and seeds of the desert plants 

 which today grow upon them but whose center of distribu- 

 tion is much farther to the south. 



On the west, Mink Creek, City Creek and Trail Creek 

 come down from the hills through narrow canyons which they 

 have cut across thq bench. Several miles south, Rabbit 

 Creek comes into the valley from the older broken country 

 to the southeast. Pocatello Creek meanders about the east- 



