石せき炭たん紀きせきたんきMeanings1nounCarboniferous periodgeologyGeological period spanning roughly 359 to 299 million years ago, known for extensive coal-forming forests.石せき炭たん紀きには巨きょ大だいなシダ植しょく物ぶつが繁はん茂もしていた。During the Carboniferous period, giant ferns flourished.