554 
the heights, they appear to have collected in a basin in the 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 about 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 with 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. 
