These footprints are something of a mystery: fossils for even the earliest bird ancestors don't show up for another 60 million years. These footprints have been known about for many years, but ...

but exactly how true birds evolved during the Mesozoic is a bit of a mystery. Adding to this conundrum are fossilized footprints of bird-like tracks that are 210 million years old—a good 60 ...

Then a light rain fell onto the ash to create something like wet cement -- an ideal material for trapping footprints. Birds and mammals left a great number of prints, but, spectacularly ...