Nonconformity in the Grand Canyon, AZ.

Arrow points to contact of Cambrian Tapeats Sandstone on Precambrian Vishnu Schist.
Note that the slopes above the Tapeats are underlain by shale (Bright Angel Shale) and the
cliffs above that are limestone (Muav Limestone). This sequence of rock types, sandstone,
shale, to limestone, indicates transgression of the sea onto the Cambrian continent.

To see another, more complicated view of this unconformity, click here.

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