22227 - Great Collection of 2 Perisphinctes virguloides Late Jurassic Ammonite - Madagascar Olcostephanus Plagioclase is partially altered and

Plagioclase is partially altered and twins are common

083g of this RARE type of MARTIAN Shergottite METEORITE

Superb huge and nicely preserved specimen

Age range: 318

The quartz is heated to 871 °C (1600 °F) in a vacuum

22227 - Great Collection of 2 Perisphinctes virguloides Late Jurassic Ammonite - Madagascar Olcostephanus Plagioclase is partially altered andGreat Collection of 2 Perisphinctes virguloides Late Jurassic Ammonite Madagascar. Perisphinctes sp, (ammonite) Cephalopoda Ammonoidea Perisphinctidae Perisphinctes is an extinct genus of ammonite cephalopod. They lived during the Middle Late Jurassic Epochs and serve as an biostratigraphic index fossil for that time period. This species of Perisphinctes comes from the classic locality of the Upper Jurassic (Oxfordian stage) of Madagascar.