FIGURE 1. Location of the White Clay Creek leaf mat site, Chester County, Pennsylvania.
FIGURE 2. White Clay Creek leaf mat site, illustrating the contact (at trowel) between the darker hydric soil layer containing subfossil leaves and the overlying, lighter-colored legacy sediments. Stadia rod for scale.
FIGURE 3. Alnus serrulata (Hazel Alder), EMS 425002. 1, Whole specimen; 2, Peltate scale and simple trichomes; 3, Stipitate gland trichome; 4, Detail of teeth; 5, Trichomes at vein junction; 6, Areolation with simple and branching freely ending veinlets.
FIGURE 4. Fagus grandifolia (American Beech). 1, Leaf fragment, showing regularly spaced secondary veins, EMS 425004; 2, Detail of venation on EMS 425004; 3, Trichomes at vein junction, EMS 425004; 4, Trichomes at the vein junction of a modern F. grandifolia leaf from York County, Pennsylvania (collection Y1.2 of Wilf, 1997); 5, Rounded tooth on subfossil, EMS 425005; 6, Tooth and rounded sinus on modern F. grandifolia leaf from York County, Pennsylvania (collection Y1.2 of Wilf, 1997); 7, Trichome, EMS 425004.
FIGURE 5. Quercus Section Lobatae (Red Oak group). 1, Leaf fragment showing asymmetrical lobe with acute apex, EMS 425011; 2, Abaxial leaf surface of EMS 425011, with randomly oriented stomata; 3, Simple trichome on leaf surface near secondary vein, EMS 425011. 4, Trichomes along a tertiary vein, EMS 425011; 5, Individual stoma of modern Q. rubra from York County, Pennsylvania (collection Y2.3 of Wilf, 1997) showing T-shape junction; 6, Individual stoma of EMS 425011.
FIGURE 6. Quercus Section Quercus (White Oak group). 1, Lobe of modern Q. alba from York County Pennsylvania (collection of Wilf, 1997); 2, Subfossil, EMS 425008, showing entire margin with fimbrial vein and retuse, asymmetrical apex.
FIGURE 9. Acer negundo (Box Elder). 1, Leaflet, showing shallow lobes and rounded sinuses, EMS 425016; 2, Trichomes along veins, EMS 425016; 3, Trichomes along tooth margin, EMS 425016, with increased density on basal side of tooth; 4, Tooth of modern A. negundo from York County, Pennsylvania (collection Y2.2 of Wilf, 1997), showing the same general trichome pattern.