THE NORTHERN PACIFIC ROUTE. 19 
great value in the subsequent development of the region. The engi- 
neers of this expedition explored most of the prominent passes through 
the Rocky Mountains in Montana and the Cascade Mountains in 
Washington, and practically outlined the route that was followed by 
the Northern Pacific engineers some 20 years later. 
In the vicinity of the village of Clear Lake the railway passes from 
the gray drift that was brought into this region by the western ice 
sheet from the Red River valley to the red drift of 
Clear Lake. the middle ice sheet. The exact point of change from 
Elevation 1,016 feet. one of these drift sheets to the other can not be deter- 
py seaneey: nisaees mined from the train, but close ebservation will show 
that there are more fragments of red rock in the drift 
north of Clear Lake than there are in the drift south of that place. 
Although the glacial drift covers this country so completely that 
the hard rocks are hidden from view, deep drilling for water has shown 
that all the sedimentary rocks ' underlying the drift in the country 
farther south have been eroded from this region and that nothing is 
left but the granitic rocks which are supposed to form the basement 
or foundation of this part of the continent. Fortunately these rocks 
are exposed at several places along the line, so that the traveler may 
see them and realize how different they are from the stratified sand- 
stone and limestone that show at the surface in the vicinity of St. 
Paul and Minneapolis. 
After passing milepost 71, beyond Cable, the train runs close to 
the State reformatory, which stands to the left of the railway. The 
walls and buildings of this institution are constructed of blue-gray 
granite quarried on the premises. The granite is an excellent building 
stone, bemg durable and of pleasing appearance, and beyond the 
reformatory it is quarried commercially. The stone can be obtained 
in fairly large blocks, and it has been used extensively in St. Paul and 
Minneapolis and shipped to different parts of the country.? <A large 
' Sedimentary rocks are those that were 
laid down as sediments, either in lakes or 
inthesea. They were deposited layer upon 
layer, and these layers show to-day in what 
Fe berets rR I 3: + 4° a2 ¢ 
£ 
the rocks. Where the material deposited 
was very fine and was supplied in small 
amounts and intermittently the layers are 
very thin, in some places as thin as paper; 
but where the material deposited was 
coarse and was supplied in great abun- 
dance, or where it was of such character 
that it did not form distinct layers, the 
beds may be very thick or even massive— 
that is, they may show no bedding planes. 
? The quarrying of granite for buildings 
and monuments is an old and well- 
established industry in this part of the 
State. The first quarry was opened at 
East St. Cloud in 1868. Since that time 
numerous quarries have been developed 
at East St. Cloud, Sauk Rapids, and 
Watab, on the east side of the river, and 
at St. Cloud and Rockville, on the west 
side. The quarries in this vicinity pro- 
duce both red and gray granites of 
that can be used only as building stone. 
In 1913 the granite quarried in Stearns, 
Benton, and Sherburne counties, with 
St. Cloud as a center, was valued at 
about $850,000. 
