The El Doctor Formation is a geologic formation in Mexico.

It preserves fossils dating back to the Albian and Cenomanian stages of the Cretaceous period.

[1] Ammonite fossils show that age of Late Albian is more likely.

[2] The light grey micritic limestone sequence with intercalated black chert lenses was deposited in an open marine basin with a hypersaline and/or poorly oxygenated bottom.

[1] The formation has provided the following fossils:[1][3][4][5][2]