"Marls appear to exist as rationale and emotion," I reasoned.
Some of the Virginia marls range as high as seventy and eighty per cent.
Some Virginia marls contain as high as seventy-five or eighty per cent.
In the marls and sandstones of the Permian period there is also much gypsum.
From 25-75% of carbonate of lime may be regarded as characteristic of the marls.
Most of these Radiolarian marls appear to date from the middle Tertiary (Miocene) period, and to be deep-sea formations.
The Aptien (or Greensand) consists generally of marls and clay.
Marls may easily be known, even by those not at all acquainted with chemistry.
The Jurassic limestones and marls contain asphalte and bituminous slate.
It also occurs in veins among the Serpentine rocks and marls.