The April 2022 General Meeting was held on Friday, April 8th, 2022. The presentation was "Seeing the Forest for the Fossil Trees - Plants at Red Hill" by Dr. Walt Cressler of West Chester University in Pennsylvania.
Red Hill is known for the First Modern Tree and a bunch of very early vertebrates. For information about Red Hill plants, see this page at the Devonian Times.
The First Modern Tree
Archaeopteris spp. account for slightly more than half of the identifiable plant fossils collected at the floodplain pond facies of Red Hill; the pre-fern Rhacophyton accounted for most of the rest. Typically, these fossils were relatively intact abscised branches that were probably blown by the wind into the floodplain pond from elsewhere in the floodplain. Larger woody fossils (i.e., trunks or large branches) have yet to be collected, but one likely and several suggestive root casts have been found. The fossils collected at Red Hill are assignable to four species based on leaf morphology. Most belong to either Archaeopteris macilenta or A. hibernica. Two other species, A. halliana and A. obtusa, were much less frequent.
The co-dominance of Archaeopteris and Rhacophyton at Red Hill is typical of Late Devonian floodplain localities from the Catskill Delta (New York, Pennsylvania, Virginia, West Virginia). Archaeopteris was also common to abundant in some near-marine Catskill localities, primarily as sea-drifted logs (form genus Callixylon). In addition, Archaeopteris-dominated forests are common in Late Devonian localities from elsewhere in Euramerica (North America and Western Europe), Gondwana (Africa, Antarctica, Australia and South America), China and Siberia. It has been found at paleolatitudes ranging from equatorial to sub-polar. From its first appearance in the middle Frasnian Archaeopteris quickly became an important and typically dominant component of the flora. Indeed, it became the lynchpin of the first true forests. Archaeopteris remained paramount until the end of the Devonian, at which time it mysteriously became extinct.
Fossil of Archaeopteris halliana. Photo courtesy of Walt Cressler.
