The
Middle Jurassic is the second
epoch of the
Jurassic Period. It lasted from 176 to 161
million years ago. In European
lithostratigraphy, rocks of this Middle Jurassic age are called the Dogger. This name in the past was also used to indicate the Middle Jurassic epoch itself, but is discouraged by the
IUGS, to distinguish between rock units and units of geological time.