Echinodermata; Class Crinoidea, Disparida, Order Uncertain
Time: Lower Devonian (Seigenian/Emsian Stage)
15 mm - 80 mm, 45-205 mm with stems attached on a 285 by 145 mm matrix
Site: Hunsrück Slate, Bundenbach, Germany
is an example of the finest of fossils from the Hunstruck Slate
near Bundenbach, Germany. The assemblage has eight complete and
partial Disparid crinoids known as Triacrinus.
Hunsruck slate at Bundenbach is famous for its fossils, many of
which have pyritization present. Rapid burial and pyritization was
what led to the many wonderful examples of early Devonian organisms
from the region. The chemistry of the silt was such that low organic
content and high levels of iron and sulfur allowed the pyrite to
diffuse into the tissues rather than be deposited in the sediment.
The mudstones were metamorphosed into slate during the Carboniferous.
slate was quarried for roofing tiles, and the workers would save
the fossils for later sale. Now that the quarries are no longer
open, future supplies of these wonderfully preserved benthic organisms
will only come from existing collections. These specimens show a
distinct orientation due to a current that flowed from left to right
across the piece as pictured. The pyritization serves as an artistic
counterpoint to the rich black slate, making for a truly striking
display piece. Fossils of this quality from the site are seldom
fossil pictures to enlarge