Top and bottom--Students and their professors from a university and a community college help the late paleobotanist Howard Schorn (bottom photo, standing in trench in pale blue long-sleeve shirt and wearing a hat)--former Collections Manager of fossil plants at the University California Museum of Paleontology--collect fossil leaves during a two day expedition to classic Lygodium Gulch, not far from Ione, California, on private property, in the middle Eocene Ione Formation, approximately 49 to 45 million years old. The Ione is one of three fossil plant-bearing Tertiary Period rock formations one can examine in California's Gold Country, western foothills of the Sierra Nevada, along the route to the upper Miocene Disaster Peak Formation paleobotanical locality in the High Sierra Nevada, Alpine County; the other two are the late Oligocene to lower Miocene Valley Springs Formation and the upper Miocene Mehrten Formation. Two supplemental areas in the California's High Sierra Carson Pass region--east of Jackson (county seat of Amador County)--also yield Tertiary-age petrified wood and fossil leaves from two unnamed (in the published scientific literature) geologic rock formations of middle Miocene age.

In addition to abundant, as-yet unidentified leaves (as of 2018, no scientific analysis of the Ione Flora has ever been published in the peer-reviewed paleobotanical literature), Lygodium Gulch also yields important specimens of the species for which the locality was informally named--an extinct climbing fern, Lygodium kaulfussi, whose closest living analog is the American climbing fern, Lygodium palmatum, now endemic to the US southeast, from roughly Appalachia to the South. Top image snapped on October 27, 2002; bottom photograph taken on October 26, 2002.