The antiquarian, Samuel Anderson dug into several barrows in the vicinity of Whitby during 1850's and his notes describe "curious figured stones" in a barrow on Newton Mulgrave Moor. This barrow has been tentatively identified by Smith (1) as one of a group of barrows at NZ 7712 1380 that still exist on the moor.

A visit to the area showed that there are no obvious carved rocks in the vicinity of the mounds although an unusual stone was noted alongside a nearby drystone wall. (see pic on right).
One side of the stone has a deep basin (approx 10cm dia and 10cm in depth) and on its underside edge there is a smaller depression (similar to a cup mark) with pick marks visible in it. There are other marks on the stone which may be plough damage.
In Scotland rock cut basins have been reportedly used as a mortar for preparing pot barley.

(1)