266 



GEOLOGICAL SURVEY OF THE TEEEITORIES. 



settlements in it. Fort Sliaw, situated about six miles east of the 

 Helena Guide Mountains, is the highest settlement in the valley. 

 Lower down, about four miles, is the Sun River crossing, on the main 

 road from Helena to Fort Benton, around which there are several farms 

 under cultivation. From this point to its junction with the Missouri, 

 a distance of some twenty-five miles, the valley increases in width from 

 three to five miles. There is some cotton-wood and aspen along the 

 banks of the stream, but other timber is scarce, and will have to be 

 hauled from the mountains. The higher table-lands, on the north and 

 south, offer most excellent grazing fields, the soil being generally very 

 fertile, that of the plateau on the north needing but irrigation to make 

 it as productive as the bottoms of the valley. 



The following statistics, from the records kept at Fort Shaw, will fur- 

 nish some data in regard to the climate of this part of the Territory : 



Monthly means of the temipefature for tivo years. 



January 21. 28 



February 30.39 



March..' ,, . 36,58 



April 46.51 



May „ 56.04 



June 64.98 



July 70.22 



August 67.15 



September 54. 04 



October 49.12 



November 39.92 



December 26. 75 



Year 47.33 



Average monthly and yearly amount of rain and Tnelted snoio for two years. 



Inches. 



January 11 



February 24 



March 

 April 

 May - 

 June . 

 July . 



.44 



.54 



1.53 



2.63 



.78 



Inches. 



August 27 



September 95 



October 75 



November .39 



December 33 



Year 8.951 



This shows a very moderate climate for this northern latitude, com- 

 paring, as has been asserted by Mr. Granville Stuart, very favorably 

 with that of Utah ; the mean temperature of the seasons being as fol- 

 lows : Spring, 46.38 ; summer, 67.45 5 autumn, 47.69 ; winter, 29.47. 



The amount of rain-fall during the growing season, from March to 

 July inclusive, is 5.92 inches, less than one-third of what is necessary 

 to supply ordinary crops. The monthly means of the winds for the 

 range of two years was, without exception, from the west. 



The valley of the Missouri from the Three Forks to the mouth of Sun 

 Eiver is very rich and fertile, but rather narrow, varying from three to 

 eight miles in width ; but at some points the hills close in upon it, leav- 

 ing but a narrow strip of bottom-land along the stream. The length of 

 the valley between these points is about one hundred and fifty miles. 

 It is tolerably well settled, the climate being mild and the productions 

 as varied as any portion of the Territory. Wheat, oats, rye, barley, 

 corn, and the usual vegetables grow well and produce heavy crops, 

 Helena receiving a large part of its supply of vegetables from this val- 

 ley. Such fruits as apples, plums, cherries, currants, raspberries, and 

 gooseberries may be grown and matured here, the climate presenting 

 no serious obstacle. 



As a general thing, after leaving the rapid descent near the base of 

 the mountains, and entering upon the broad, open plains, the rivers of 

 this section run in deep channels, which like great ditches traverse the 

 plains, and are often for long stretches sunk from 100 to 150 feet below 

 the surface. 



