El Doctor Formation
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. Ammonite fossils show that age of Late Albian is more likely.
Description
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.Fossil content
The formation has provided the following fossils:;Fish
- Squalicorax falcatus
- Ptychodus decurrens
- Rajiformes
- Enchodus zimapanensis
- Xeneichthys yanesi
- Heckelichthys preopercularis
- Motlayoichthys sergioi
- Nunaneichthys mexicanus
- Ichthyotringa mexicana
- Muhichthys cordobai
- Dalgoichthys tropicalis
- Handuichthys interopercularis
- Pseudomonocentris microspinosus
- Araripichthys sp.
- Vinctifer sp.
- Pachyrhizodus sp.
- cf. Tselfatia
- Pycnodontiformes
- Cladocyclidae
- Elopiformes
- Gonorhynchiformes
- Mawsoniidae
- Aeger hidalguensis
- Polzia eldoctorensis
- Victoriacaris muhiensis
- ''Palinurus sp.''
Ammonites
- Mortoniceras sp.
- Hamites aff. renzi
- Beudanticeras sp.
Echinoderms
- Echinoidea
- Crinoidea