John Allen Howe

“ A somewhat similar deposit, a “conglomérat de silex” or “argue à silex,” occurs at the base of the Eocene on the southern and western borders of the Paris basin, in the neighbourhood of Chartres, Thimerais and Sancerrois. ”

“ Many geologists have supposed, and some still hold, that the Clay-with-Flints is the residue left by the slow solution and disintegration of the Chalk by the processes of weathering; on the other hand, it has long been known that the deposit very frequently contains materials foreign to the Chalk, derived either from the Tertiary rocks or from overlying drift. ”