854 



the heights, they appear to have collected in a basin in t;he Vallecieto dis- 

 trict of the upper Pine, now a magnificent valley from a mile to several 

 miles wide and several miles in length, blocked in by mountains and ridges 

 which rise one thousand feet above the valley floor. Here the glacier 

 pushed southward, spreading out both eastward and westward into a huge 

 fan as it reached the valley flats, even crawling over the lower ridges of 

 the foothills and beginning to spread extensively before reaching the lati- 

 tude of Bayfield. The writer can not say whether the Spring Creek gla- 

 cier was a branch of the Pine River glacier, or came from another glacier 

 center in the same mountains. This much is sure, at Laboca they formed a 

 continuous ice sheet and the outwash materials coalesced. Extensive gla- 

 cial debris was also noticed al)out Pagosa Springs fifty miles east of Bay- 

 field. 



As the boulders overlie the mesas south of Ignacio, it would seem that 

 they were carried there when the glacier was higher and more extensive 

 than when it deposited the great boulder deposits in the lower benches at 

 Oxford, northeast of Durango, at Ignacio, and in the lower valley of the 

 river near the latter place. Whether two glacial stages are here repre- 

 sented could not be determined v^-ith the data obtained. 



Since glacial times the river and its confluents have cut entirely through 

 the drift at most places all the way to bed rock and have also widened out 

 a very considerable inner-valley flood plain. 



