What's in Muck

These are bits of leaves and other plant fragments in a matrix of clay and quartz sand. Mostly clay (green). The white blebs are sand.
The size of the largest leaf remnant in the center is about 0.5 cm.

The black color of the fragments and green color of the host rock indicate reducing conditions, no oxygen present. In greater concentration, these could give rise to coal deposits.

Age of rock is about 35 million years. From the Mesohellenic Trough, near Tsouliakas, Greece.