Two views of the same prolific fossil horizon in the Middle Eocene Ione Formation, Ione Basin, western foothills of the Sierra Nevada, Amador County, California. At top is a scenic overview, looking roughly northeast--the red backpack marks the precise locality of the leaf-bearing horizon; at bottom is a closer look at the lithology of that same fossil site in the Ione Formation--the leaf-yielding rocks, at the red backpack, consist of whitish to reddish-brown feldspar-rich shales and sandstones that were deposited during periodic episodes of flooding along the eastern shores of the great inland sea, which during lower to middle Eocene geologic times covered California's Great Central Valley. This particular fossil horizon occurs in the vicinity of Lygodium Gulch (named after the rather common to abundant remains of a fossil climbing fern, Lygodium kaulfussi, whose closest modern counterpart is the living Lygodium palmatum, now native to Mississippi, Alabama and Georgia north to New England); Lygodium Gulch is certainly one of the great fossil leaf localities in the Ione Basin. Image taken on March 8, 2004.
Please note: All fossil localities in the Ione Formation of Amador County, California, presently occur on private property; explicit permission from the land owners must be secured before collecting fossils there.