James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 1
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 2
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 3
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 4
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 5
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 6
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 7
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 8
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 9
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 10
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 11
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 12
James St. John:
Faulted geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico)
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 1
James St. John:
Cracking a geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 1
James St. John:
Cracking a geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 2
James St. John:
Cracked geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico)
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 13
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 14
James St. John:
Agate-filled geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 15
James St. John:
Geodes and agate-filled nodules (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico)
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 2
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 3
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 4
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 5
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 6
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 7
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 8
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 9
James St. John:
Geode (Las Choyas Geode Deposit, near-latest Eocene, ~35 Ma; Chihuahua, Mexico) 10
