When excavated in 1879 the cave was measured at 27 ft long and 6 ft high and wide for 15 ft to the rear. The excavation went down to a depth of 6 ft before hitting bedrock and three levels were discernible, each made up of layers of well trodden ashes and sea shells, the first at 18 ins, a second at 30 ins, and the basal layer at 39 ins deep. Many bones were found including: Deer, cat, pig, horse, sheep, goat, ox, and rabbit bones were found, the horse bones between the upper and second level with dog bones between the middle and basal levels.
A significant find was a bone object with a rectangular hole at one end found on the second level and a flint object was found just above the basal level. An object made of slate object was found. Some pottery fragments were found including a coarse, unglazed, reddish appearance and a thinner example with a green-brown glaze similar to Scottish Medieval pottery. The National Museum of Scotland holds the bone implement and some pottery fragments.
Wikipedia: The Holy Cave, Hunterston.
Link
Canmore ID 40667
Link