Complex sentence: Glauconite particles are one of the main components of greensand, glauconitic silstone and glauconitic sandstone, and glauconite has been called a marl in an old and broad sense of that word.
Split into simpler sentences: Glauconite particles are one of the main components of greensand, glauconitic silstone and glauconitic sandstone. Glauconite has been called a marl in an old and broad sense of that word.