Quercus sp.
Angiosperm
Middle Miocene (Mohnian)
Aguajito Shale Member, Monterey Formation
Carmel, California, USA

27mm oak leaf with insect damage on 106mm slab.

Plant. Trace fossil.

Quercus is the genus for oak trees.  The earliest confidently-known fossils are pollen from the Late Paleocene of Austria, and by the Middle Eocene, oaks are known from North America, Europe, and Asia.  Quercus originated in tropical forests but they continued to thrive while other trees retreated to lower latitudes as climates became drier and cooler across the Oligocene and Miocene. 

This 15 million year-old specimen vividly exhibits insect damage mirroring what we can find on the ground today.