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Showing results for tags 'spinatum zone'.
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Original shell material. This species has a wide range of variation. Not all specimens have such pronounced spines.
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- a493
- buttenheim
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(and 4 more)
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This sample still has a white substance covering it which is original shall material. This is the index fossil for the apyrenum subzone. Old German Chronostratigraphy: Lias (Schwarzjura) delta Literature: Simonsen,S. et al (2012): Die Tongrube Buttenheim, 2. überarbeitete Auflage, Verlag Der Steinkern
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- a1150
- amaltheenton formation
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The first three photos show an extremely well-preserved specimen of this species which was gifted to me by an aquaintance. The last three show an accumulation of strongly pyritized ones from the clay pit at Buttenheim in Bavaria, the largest of which has a diameter of 5cm. This is the index fossil for the spinatum zone and also for the spinatum subzone, an informal designation in Germany. The clay pit at Buttenheim is world-reknowned for its upper Pliensbachian ammonite fauna. It is one of, when not the best site worldwide for studying the breadth of variation and development of form through time, particularly of the various species of the genus Pleuroceras. Zones, subzones and horizons are all easily accessible and layed out like the pages of a book here. This species looks quite similar to P. solare, but is relatively easily distinguishable upon closer study. The extremely strong ribs rise to a point slightly above the keel, whereas the somewhat weaker ones of P.solare lie a little below its keel. The whorls of P.spinatum are also somewhat wider than those of P.solare. Old German Chronostratigraphy: Lias (Schwarzjura) delta Literature: Simonsen,S. et al (2012): Die Tongrube Buttenheim, 2. überarbeitete Auflage, Verlag Der Steinkern
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- a369 & a1148
- altdorf
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