GLACIAL DEPOSITS IN PINE RIVER VALLEY, COLORADO. 
BY 
ALBERT B. REAGAN. 
The table-flats at Florida, east of Durango, Colorado, on the Denver & 
Ric Grande Railway and eastward across Pine river to beyond Spring creek 
at Laboca on that railroad—in fact, the whole area from the bluff-mesas 
west of Durango to the bluff-mesas beyond Spring creek to the eastward in 
a curve running to the northeast of Durango and bending far to the south- 
ward and southeastward, is covered heavily with glacial drift, except 
where the country rocks project above it in points, ridges, and buttes in 
many places. The mesas southwest of Ignacio are also covered with 
glacial boulders and other glacial material. How much farther the glacier 
extended is not known to the writer. 
A little northeast of Durango in the Animus yalley there are heavy 
morainic deposits, associated with extensive outwash deposits. The same 
phenomenon appears on the Florida, above and in the vicinity of the station 
of the same name. At Oxford the outwash material, loess, etc. is ten feet 
deep, superimposed on a bed of boulders often from ten to twenty feet in 
depth. West of Ignacio the outwash material butts up against the mesas, 
being often twenty feet thick in the valleys. At Ignacio and at the South- 
ern Ute Boarding School a mile to the northward, the outwash and 
upper till loess and adobe clay is from five to ten feet deep back from the 
mesa’s edge of the first bench. Immediately underneath this are from five 
to twenty-five feet of boulders underlain in places by lower till. At Laboca 
only outwash material was seen, there often forty feet thick, as is shown 
in the valley cuts of the present washes. 
Three miles north of the present Indian school on Pine river, the stream 
has cut completely through the debris, which here shows no lower till, 
but twenty-five feet of boulders on which are superimposed outwash till and 
loess. The bench west of the boarding school, to which a part of the school 
land extends, is one hundred feet above Pine river in elevation, but at no 
place in the slopes from the river to its crest is the original rock shown. 
On top of the bench are five feet of adobe, beneath which are twenty-five 
feet of boulders, and under this till to an unknown thickness. At Bayfield, 
ten miles north of Ignacio, the outwash material is of immense thickness, 
overlying boulders; while to the southeast of that city over a small ridge of 
jutting, original country rock buttes, is a pocket of glacial deposits of a 
similar nature. Also from Bayfield northward on Pine river for many miles, 
outwash material is very conspicuous. The valley fillings seem to be 
composed wholly of it. 
The glaciers that made these deposits seem to have had two or more 
centers. The glacier in the vicinity of Durango appears to have come down 
the Animus river channel. The rest of the glaciers seem to have had their 
origin in the lake country above the junction of Vallecieto creek and Pine 
river in the high peaks of the San Juan range. Pushing downward from 
