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Baculites are a relatively straight shelled ammonite. They start out with a curved shell, like the coiled ammonites, called an ammonitella. The ammonitella is quickly followed by a straight to slightly curved shaft. The shape of the cross section of the shaft can be circular, oval, elliptical, triangular, or pear shaped. Ribs occur along the sides as undulations or slight swellings which can be low (almost smooth) to high. It is these differences which distinguish the different species. The different species of Baculites are important index fossils where they occur in the Pierre Shale.
Of the species present in South Dakota, Baculites compressus and Baculites cuneatus are the most common. Baculites compressus is easily identified by its compressed and relatively smooth sides. Baculites cuneatus is more triangular shaped with well developed undulations along its sides. Both species have very complex suture patterns.
Many of the Baculites from South Dakota will fluoresce due to the replacement of the shell by calcite and chalcedony. The calcite will fluoresce from white to yellow to orange. The chalcedony usually shows up as a green fluorescence. Usually the stronger fluorescence is under long wave and is the first photo shown. The photo below is the short wave photo. Chalcedony usually does not fluoresce well under long wave, but does fairly well for the fossils from this area.
To see a photo of this specimen under normal light click on the Baculites link from the Fossils section on the side bar. Also check out other South Dakota fluorescent offerings under the Fluorescents section. Then click on the to view specimen material from South Dakota link. Some normal light photos will be shown there.
This specimen is a side view cross section from front to back. It shows two nearly complete chambers filled with crystals. In some specimens the chambers will alternate yellow and dark orange-red calcite under normal light. The short wave photo is shown below. The purple color is the reflection of the light off the light colored specimen and is not fluorescence.
Baculite
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Quantity in Basket:
None
Code: SDB-104
Price: $15.00
Shipping Weight: 0.08 pounds
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Time: Upper Campanian Stage of the Upper Cretaceous, approximately 73-72 million years ago.
Location: South Dakota, USA
Dimensions: 1-7/8" x 1-1/4" x 1/2"
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