marlstone

marl +‎ stone

marlstone (countable and uncountable, plural marlstones)

1. (geology) Marl when hardened into stone.
   • 1961 July, C. P. Walker, P. H. V. Banyard, “Leicester's Belgrave Road branch lives another year”, in Trains Illustrated, page 414:

     The steady climb eastwards has lifted us from the Soar Valley at Leicester into the marlstone (or ironstone) country of the Middle Lias which, at this point, forms a ridge of high ground over 700ft above sea level, […]

• “marlstone”, in Lexico, Dictionary.com; Oxford University Press, 2019–2022.

• loan terms, mestranol, normalest