Calamites Stem Fragment
Calamites cf. suckowii • Body fossil (compression/mold); Plant fossil (Palaeobotanical)
Geological Period
Carboniferous (specifically Pennsylvanian sub-period)
Estimated Age
299 to 359 million years
Preservation Type
Pith cast (internal mold) formed by sediment filling the hollow center of the stem; partially permineralized with fine-grained sediment.
Condition Assessment
Fair to Good; the ribbing is distinct, but the specimen is a fragmentary segment lacking nodal junctions and showing significant weathering.
Taxonomic Classification
Kingdom: Plantae; Phylum: Pteridophyta; Class: Equisetopsida; Order: Equisetales; Family: Calamitaceae; Genus: Calamites
Morphological Description
A cylindrical section showing prominent longitudinal ribbing (striae) and grooves. The ribs are parallel and separated by narrow furrows, which are the internal pith cast impressions of an ancient giant horsetail. No visible nodes (joints) are present in this specific fragment.
Rock Matrix
Sandstone or silty mudstone; likely ferruginous (iron-stained) given the tan/orange coloration.
Formation & Location
Commonly found in the Coal Measures of the United Kingdom, the Appalachian Basin (USA), and the Mazon Creek area (USA).
Size & Dimensions
Approximately 5-8 cm in length and 3-4 cm in diameter; a small to medium-sized fragment compared to the full 30-meter height of the living plant.
Value & Rarity
Estimated Market Value
$10.00 - $25.00 USD
Auction Estimate
$15.00 - $30.00 USD
Rarity Assessment
Common; Calamites fragments are ubiquitous in Carboniferous coal-bearing strata worldwide.
Scientific Significance
Provides evidence of the 'Coal Forest' ecosystems; illustrates the gigantism of Carboniferous flora and the evolutionary history of modern horsetails (Equisetum).
Preparation Recommendations
Requires minimal preparation; dry brush to remove loose dust. Store in a low-humidity environment to prevent any potential pyrite decay if present in the matrix.
Notable Features
Features distinct, evenly spaced vertical grooves which represent the vascular structure of the plant's internal pith cavity.