Dane-hole

In this manner, likewise, the numerous so-called “Dane-holes” in Kent and Essex were worked for some purpose not yet distinctly ascertained."

We may add that a “Dane-hole” partly filled up is to be found in the Stifford chalk quarry.

...both the gold and the money were hidden in the Tin-hole or Dane-hole.

“A Dane-hole? Here?” asked Carolus, the history master in him almost as interested as the detective.