Aubrey calls this "a conglobation of gravel and sand," and says that the inhabitants know it as "the Devil's Stone, and believe it cannot be mov'd, and that treasure is hid underneath.".    From Wordnik.com.  [Highways and Byways in Surrey] Reference

A very lucid explanation certainly, but rendered a little difficult of apprehension by the effort necessary for realising in a mental picture the conglobation of a fulgureous exhalation by a circumfixed humour.    From Wordnik.com.  [Falling in Love With Other Essays on More Exact Branches of Science] Reference