AZGS has re-issued the first statewide geologic map of Arizona in recognition of our 125th anniversary this year. The Geologic Map of the State of Arizona, 1924, by N.H. Darton, C. Lausen and E.D. Wilson is online for free downloading. The authors were all leading lights of the early years of geologic exploration in Arizona. The original map was published at 1:500,000.
Parkinsonia parkinsoni Ammonite Fossil
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