View looking
toward the west with Bass Canyon entering from the left in
the center foreground. In Precambrian time, a fault at
Bass Canyon dropped the strata to the right (downstream)
downward. This shows up today as a sudden disappearance of
the riverside cliff.
Shinumo Creek enters the river in the middle
of the “S” curves at the lower right. Shinumo Creek drains
a large area, and in the past its debris fan has pushed
the Colorado River to the left thereby forming the “S”
curves.
The lack of a large debris fan at the current
time would indicate there haven’t been any large debris
flows in recent history. However, there is still enough
debris left to partially dam the river with the result
that river gradient in this section is second only to the
Hance Rapid portion of the river. At some point in the
past (and possibly again sometime in the future) there was
a major rapid here.
In the upper right portion of the picture,
the green area represents the forested top of the Powell
Plateau. The long ridge extending to the left is Marcos
Terrace. Walthenberg Canyon is directly in front of it
(before the river starts the long bend to the left), and
both Marcos Terrace and the walls of Walthenberg Canyon
show the classic massive cliff of the Redwall/Muav
Limestones. (Note, both the Belknap and Stevens River
Guides incorrectly omit the “h” in Walthenberg.)
Return
to river miles 96 to 104
Continue
to
river miles 112 to 120
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to
the Index Page for the Grand Canyon Tour
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