232 GEOLOGICAL SURVEY OF THE TEERITORIES. 



The ]3ortioi3. of country north of the Cache a la Poudre valley, although 

 affording good pasturage for cattle and sheep, is not generally included 

 in the estimate of arable land, on account of its lack of irrigating facili- 

 ties. Yet the Box Elder Valley is quite fertile, and will afford room for 

 a considerable number of good farms, and the creek, though small, is 

 probably sufficient to irrigate the red bottom of the valley. 



Commencing with the Cache a la Poudre, as the northern limit of the 

 section, which is some seventy miles north of Denver, and proceeding 

 south, I will describe briefly the valleys according to the streams which 

 water them. This stream, from the point wh6re it issues from the 

 mountains, near Laporte, to its junction with the Platte, a distance of 

 thirty-five miles, runs through a very pretty fertile valley, which aver- 

 ages, perhaiJS, two miles or more in width, being narrow near the moun- 

 tains and expanding as it recedes from them. The bottom land of the 

 valley is flanked on the north side by a rolling irregular ridge, and on 

 the south side by a somewhat level terrace of moderate elevation. The 

 stream, at Lai)orte, is about twenty-five yards in width, clear and rapid, 

 affording a sufficient supply of water and ample descent for irrigating 

 the bottoms and ridges or terraces which border it. 



The liext stream, going south, is the Big Thompson, which runs east- 

 ward nearly thirty miles, and also empties into the South Platte. This 

 stream, and the valley it waters, are very similar in all respects to that 

 of Cache a la Poudre. The third, is the Little Thompson, a tributary of 

 the Big Thompson, but, as this creek is liable to fail in its supply of 

 water during the summer and autumn, it cannot be relied upon for irri- 

 gation. Yet its valley affords excellent pasturage for cattle and sheep, 

 and will furnish a most excellent range for stock when the neighboring 

 valleys become thickly settled and fenced up. Still moving south, the 

 next stream we cross is the St. Vrain, about equal in its volume of water 

 to the Big Thompson. It runs through a very fertile valley of var-ied 

 width, reaching the Platte at a distance of about twenty-five miles from 

 where it leaves the mountains. The bay-like wideuings of this valley 

 afford room for extensive farms, of which the settlers are rapidly avail- 

 ing themselves. Left Hand Creek, a tributary of St. Yrain, allbrds a 

 small valley eleven miles in length. Boulder Creek, the next in order, 

 issues from the mountains near Boulder City, and, after running some- 

 what northeast for eighteen miles, unites with the St. Yrain. Some of 

 the finest farming and grazing lands north of Denver are found along 

 this stream. At its debouchure from the mountain gorge are gathered 

 heavy deposits of boulders and pebbles, from which, doubtless, the 

 creek and city have received their names. Although these deposits are 

 but scantily covered with soil, yet the fertility seems to be but slightly 

 impaired thereby, as is shown by the fact that here is a thrifty growth 

 of willow and cotton wood. 



The bottom of this valley, like that of St. Yrain, widens out at x)oints 

 to a considerable extent. Continuing our coiu-se southward with the 

 snow-covered peaks rising above the rocky wall to our right, we next 

 arrive at South Boulder Creek, which, leaving the mountains near Mar- 

 shall's coal mine, runs a circuit of some eight miles and unites with 

 Boulder Creek. Here, I may justly say, is found the link that unites 

 the agriculture of the plains with the mining of the mountains^ the two 

 great interests of Colorado. 



Standing on the grass-covered bluff' overlooking this little limped 

 stream, the eye, as it shoots out its glance north and east over the 

 plains, wearies itself in attempting to mark the bouudarj^ of vision. 

 The valleys over which we have passed in our journey southward, 



