The Aalenian is a subdivision of the Middle Jurassic Epoch/Series of the geologic timescale that extends from about 174.7 ±0.8 Ma to about 170.9 ±0.8 Ma. It was preceded by the Toarcian and succeeded by the Bajocian.
In the geologic timescale, the Bajocian is an age and stage in the Middle Jurassic. It lasted from approximately 170.9 ±0.8 Ma to around 168.2 ±1.2 Ma. The Bajocian Age succeeds the Aalenian Age and precedes the Bathonian Age.
Barns Batch Spinney is a 0.06-hectare geological Site of Special Scientific Interest near the village of Dundry, North Somerset, notified in 1987.
Stephanoceras is an extinct genus of Stephanoceratoid ammonite which lived during the Bajocian. It is the type genus of the family Stephanoceratidae.
Abbasites is an extinct genus of ammonites from the early Middle Jurassic epoch, included in the ammonitid family Erycitidae.
Arcticoceras is an extinct ammonoid cephalopod genus from the late Middle Jurassic belonging to the ammonite family Cardioceratidae, more commonly found to high northern latitudes.
Arctocephalites is an extinct ammonitic cephalopod genus from the Middle Jurassic with a wide northern distribution belonging to the stephanoceratacean family, Cardioceratidae.
Bifericeras is a Lower Jurassic ammonite belonging to the family Eoderoceratidae, and sometimes placed in the subfamily Xipherceratinae. Whorls are strongly depressed, but still evolute in coiling. The early growth state is prolonged, and smooth, followed by a late growth stage with rounded, straight, bituberculate ribs.
Caumontisphinctes is an ammonoid genus from the ammonitid superfamily Perkinsonatoidea that lived during the Bajocian stage of the Middle Jurassic.
Praestrigites is a genus from the family Strigoceratidae which is included in the ammonitid superfamily Haploceratoidea.
Phaulostephanus is an extinct genus from the ammonoid family Stephanoceratidae, which is part of the ammonitid superfamily Stephanoceratoidea, that lived during the early Middle Jurassic.
Parastrenoceras is an extinct genus from the ammonoid cephalopod order Ammonitida, included in the family Spiroceratidae that lived during the Bajocian stage of the Middle Jurassic.
Hebetoxyites is a genus of ammonoid cephalopod from the middle part of the Bajocian stage, middle Jurassic, included in the Strigoceratidae, Haploceratoidea. The shell is oxyconic, with a sharp rim but no keel, and involute, with the inner whorls hidden. The umbilicus is very small. Sides have a spiral ridge but are not striate.
Graphoceras is an extinct ammonite genus included in the hildoceratacean family Graphoceratidae that lived during the Aalenian and Bajocian stages, Middle Jurassic in what is now Europe, north Africa, and Iran.
Hildoceras is a genus of ammonite from the Jurassic period in the family Hildoceratidae. The shells are characterized by a narrow discoidal evolute shape, keeled venter, concave ribs along the outer flanks, and a shallow spiral groove running along smooth inner flanks. Whorls slightly overlap, cross sections are compressed. The ventral keel is bordered on either side by a shallow groove. The genus was named by Alpheus Hyatt after Saint Hilda in 1876.
Parkinsoniidae is a family of ammonites belonging to the order Ammonitida. The cephalopod family lived from the Bajocian stage to the Bathonian age of the Middle Jurassic.
Parkinsonia is a genus of ammonites belonging to the family Parkinsoniidae.
Skirroceras is a Stephanoceratacean (ammonite) genus belonging to the family Stephanoceratidae. These fast-swimming carnivores lived during the Jurassic period, in the Bajocian age.
Hammatoceras is a genus of ammonites belonging to the family Hammatoceratidae which lived during the Toarcian stage of the Early/Lower Jurassic between about 184 and 175 million year ago.
Ringsteadia is a Jurassic ammonite.
