ITINERARY. 
The traveler who is interested in the geologic history of this 
country—a history that reaches back into the dim and misty past, 
to a time long before Father Hennepin first saw the Falls of St. 
Anthony and the Mississippi Valley in 1680—will find much to attract 
his attention about St. Paul and Minneapolis. If he has only a 
few hours at his disposal he can easily obtain a general view of the 
valley of the Mississippi and the rocks composing its bluffs from the 
Robert or Wabasha Street Bridge in St. Paul, both of which are 
within a few minutes’ walk of the Union Station. If he chooses the 
Wabasha Street Bridge, which in some respects affords a better 
view, he will see that the Mississippi is flowing in a broad valley 
from 100 to 200 feet deep. In some places the walls of the valley 
are composed of solid rock, but in others they are made up of loose 
material, such as clay, sand, or gravel, which forms either large 
masses or is spread as a thin coating over the rocky slopes. As the 
valley has been cut in the hard rock by the river, it is a record of 
stream carving and of the climatic and geographic conditions under 
which the carving was done. Not only are the recent events of 2e0- 
logic history recorded in the size and shape of the valley, but the much 
earlier events in the history of the globe have left a record in the solid 
rock itself—a record that, when correctly read, tells of the presence 
of a sea in which limy muds were accumulating or along the shore 
of which sand was washed back and forth by the waves or drifted 
into heaps by the wind. Every one is more or less familiar with 
the history of Minnesota during the last 250 years, or since the white 
man first visited the region, but few know anything of the far more 
‘ancient history recorded in the rocks and in the hills and valleys of 
.the region. It is to this ancient history, dealing with the time 
before man is supposed to have existed upon the globe, that the 
reader’s attention is now invited. 
The bluff upon which the Wabasha Street Bridge rests is com- 
posed almost entirely of white sandstone (St. Peter‘), which is very, 
very old, but despite its great age is so soft that it can be crushed in 
the hand. Streams of water flowing through the rock have carved 
great underground channels in it, and more recently boys have dug 
caves in the soft sand along the river front directly below the bridge. 
? The rocks exposed at the surface in the vicinity of St. Paul and those revealed 
by deep drilling are shown in the table on page 9. The natural order of the forma- 
tions named in the table, from top to bottom, is shown by the order in which the 
8 
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