FOOTPRINTS OF THE LATE MIDDLE DEVONIAN FOREST IN THE CATSKILLS OF NEW YORK

The origin of tree-size plants in the Middle Devonian signaled a fundamental change in Earth’s terrestrial ecosystems. Perhaps the most famous fossil locality documenting an in situ forest of this age is the “world’s oldest forest” at Gilboa in the Catskill Mountains of NY (Goldring 1927). At this site, hundreds of large sandstone cast tree bases named Eospermatopteris, now known to be pseudosporochnalean, were found rooted in life position. We had the opportunity to map a portion of the original site, previously inaccessible for nearly 90 years, and now reburied. A gleyed paleosol was still intact and provided well-preserved footprint evidence of relative sizes and positions of trees in this ancient forest. Instead of a monospecific stand, a mixed assemblage comprised of dominant Eospermatopteris plus two other tree-sized plants was found. These include the earliest known tree lycopsid in North America, and very large scrambling to ascendant plants identified as aneurophytalean. The association of typical aneurophytalean (probably Tetraxylopteris) aerial shoot systems with large scrambling main stems represents a significant clarification of the morphology of these forms heretofore considered ‘shrubs’. General features of the site suggest that the famous forest surface was one of several rooting horizons showing no direct evidence of marine influence. This, and the plants themselves, suggests an ephemeral forest in a disturbed wetland environment associated with periodic, and probably catastrophic, terrestrial flooding bringing in large bodies of sand. Although the original Gilboa site is no longer available for study, ongoing work at a nearby site provides additional and contrasting information on floral composition of a slightly older Catskill forest. Here also is seen a mixed assemblage. In addition to Eospermatopteris, we see large radiating root systems likely belonging to very early Archaeopteris, plus a strange footprint whose identity is not yet determined. The paleosol suggests a variable but generally more aerated environment than at Gilboa. This occurrence also includes well-articulated placoderms and chondrichthyans suggesting marine overwash into an adjacent lowland terrestrial environment perhaps killing the trees and preserving roots within the paleosol.