Crinoid stems in matrix

From collection Fossil collection by Lukas Wallentin

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Designation

Description

This specimen consists of a sedimentary rock matrix containing numerous fossilized crinoid stems. The matrix is a brownish-grey, fine-grained material, likely a limestone or calcareous siltstone. On the primary surface, multiple elongated, cylindrical stem sections are visible, ranging in length and orientation. These stems exhibit a characteristic segmented structure composed of stacked disc-like ossicles, known as columnals. The fossilization process has preserved the fine ridges and sutures between these segments. A side view of the specimen reveals the circular cross-sections of several stems embedded within the rock; these circular faces show the central lumen and the radiating ridges (crenulae) on the articular surfaces. The stems are primarily tan to light brown in color, providing a visual contrast against the darker greyish matrix. Some areas of the matrix show dark, possibly carbonaceous or mineralized inclusions. The overall shape of the matrix is irregular and wedge-like, with rough, unpolished edges indicating it is a field-collected fragment. No evidence of artificial reconstruction is visible, and the fossils appear to have been exposed through natural weathering or light mechanical preparation.

Scientific name

Crinoidea