Plural of calamite; multiple fossilized remains of ancient reed-like plants from the Carboniferous period.
From 'calamite' + regular plural '-s'. This creates the plural form of the fossil noun.
Calamites fossils are so common in coal seams that miners literally built their tunnels through ancient 'forests' of these 300-million-year-old plants without realizing what they were.
Complete word intelligence in one call. Free tier — 50 lookups/day.