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Twin Sisters

By Geology and Ecology of National Parks
Twin Sisters
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Detailed Description

 

The Twin Sisters are both massive outcrops of granite, however the "left sister" consists of 2.5 billion year-old granite whereas the "right sister" consists of 30 million year-old granite. The Twin Sisters are near the southern boundary of City of Rocks National Reserve (Strickand and others, [2008]).

Sources/Usage

Public Domain.