"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.