John wesley powell who led the first boat trip

10. John Wesley Powell, who led the first boat trip through the Grand Canyon, called the feature marked by the
yellow lines “The Great _________”. What did he put in the blank?
A. Unconformity.
B. Pull-apart fault.
C. Trompe L’Oeil.
D. Thrust Fault.
E. Intrusion.
This is The Great Unconformity, separating inclined sedimentary rocks below from horizontal sedimentary rocks above. The rocks above are from the
Paleozoic, and those below from the Precambrian. A Trompe L’Oeil painting is designed to fool the eye, but this is real.
Correct Answer: A
Your Response: A
Points Earned: 1/1

4/9/10 12:55 PM GEOSC 10: Geology of the National Parks (Web, merged), SP10
Page 6 of 9
11. The above photograph was taken in the Grand Canyon, and shows a cliff that is approximately 30 feet high.
What are the rocks in the cliff?
Points Earned: 1/1

4/9/10 12:55 PM GEOSC 10: Geology of the National Parks (Web, merged), SP10
Page 7 of 9
12. The picture above shows a very hard piece of rock about six inches across, in the Grand Canyon.
The surface of the rock looks rather different from the surfaces of many other rocks.
What made this odd-looking surface?
Points Earned: 1/1