Add to ORKGSmall calcareous plates, possibly from Asteroidea or other Echinodermata, occur in the Maquoketa shale of Iowa. These plates all have similar characteristics, but vary in their minute structures, and the variations apparently have some stratigraphic significance
Representatives of several genera of nautiloids are described from the Permian of western and southw...
Associated with dismembered parts of Dikellocephalus minnesotensis in the St. Lawrence limestone, at...
These geodes occur in Lime Creek shales. They are rather unusual in containing a number of roundish ...
Small calcareous plates, possibly from Asteroidea or other Echinodermata, occur in the Maquoketa sha...
Heavy accessory minerals have been separated from specimens of granite gneiss taken in a traverse ac...
Ammonoids are among the best of index fossils and are particularly useful for intercontinental corre...
A collection of fossils from the Doniphan Shale, Virgilian Stage, Upper Pennsylvanian contains a sma...
In view of the exceptional stratigraphic value of Late Carboniferous ammonoids, it seems worthwhile ...
Representatives of the ammonoid genera Perrinites and Peritrochia are described from south of Chioco...
Two specimens of edrioasteroids have been found in the Maquoketa Formation, Richmond Group, Upper Or...
This type of cephalopod began in the Devonian and became the fore-runner of the Mesozoic ammonites. ...
These microfossils were found in screenings obtained by washing some marly shales from the Cerro Gor...
Representatives of several genera of nautiloids are described from the Permian of western and southw...
Associated with dismembered parts of Dikellocephalus minnesotensis in the St. Lawrence limestone, at...
These geodes occur in Lime Creek shales. They are rather unusual in containing a number of roundish ...
Small calcareous plates, possibly from Asteroidea or other Echinodermata, occur in the Maquoketa sha...
Heavy accessory minerals have been separated from specimens of granite gneiss taken in a traverse ac...
Ammonoids are among the best of index fossils and are particularly useful for intercontinental corre...
A collection of fossils from the Doniphan Shale, Virgilian Stage, Upper Pennsylvanian contains a sma...
In view of the exceptional stratigraphic value of Late Carboniferous ammonoids, it seems worthwhile ...
Representatives of the ammonoid genera Perrinites and Peritrochia are described from south of Chioco...
Two specimens of edrioasteroids have been found in the Maquoketa Formation, Richmond Group, Upper Or...
This type of cephalopod began in the Devonian and became the fore-runner of the Mesozoic ammonites. ...
These microfossils were found in screenings obtained by washing some marly shales from the Cerro Gor...
Representatives of several genera of nautiloids are described from the Permian of western and southw...
Associated with dismembered parts of Dikellocephalus minnesotensis in the St. Lawrence limestone, at...
These geodes occur in Lime Creek shales. They are rather unusual in containing a number of roundish ...