Here are 7 real limestone caves in Cornwall. There are many more, but you need to buy the book:
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HOLYWELL CAVES
CAVES ON NORTH SIDE
Going from south to north
Cave 1 (Movies A/B) NGR
This is adjacent to Cave 2 This cave is about 10 ft high and 10 ft wide at the entrance with signs of stal on the rocks above the cave.
It goes back about 70 ft and is about 15 ft high. There is a big wall of stal about 30 ft long, coming down into the cave
Cave 2 (Movie A ) NGR
50 yards down from Cave 1 and set back in a small bay.
It has an entrance about 50 ft high and about 20 ft wide, and it goes back about 30 ft, and then continues under a small overhang into a small chamber, about 15 ft high and 7 ft in diameter, with the remains of stalactites on the back wall.
Cave 3 (Movie 9) NGR
Adjacent to Cave 2, a slot cave goes up 30 ft back 15 ft and 3 ft wide.
Cave 4 (Movie 8) NGR
4 ft high and 4 ft wide 20yards from Cave 3
Cave 5 Rock Shelter NGR
50 yards South of Cave 6 Movie 7
Cave 6 NGR
50 yards north of Cave 5 Movie 6 A slot cave with a deep pool in the entrance, it has an entrance about 15 ft high and goes into a chamber about 4 ft round.
CAVE 7
HOLYWELL CAVE ? (Movies 1,2,3,4,5)
Near the end of the cliffs on the north side of the bay above low water mark. The cave is in a gully, and it is easier to find by walking to near the end of the cliffs above low water mark, and looking back to spot the gully. This is basically a bedding plane cave, with an entrance about 30 ft high. The cave goes back for a further 40 ft and slopes up about another 30 ft on the northern side.
It is about 25 ft wide throughout with rough boulders in the floor. In the entrance are a series of limestone pools for which the cave is famous. Just visible outside the cave are a series of slippery steps leading up to these pools.
Although you can only get in the cave at low tide, if you were cut off it would be possible to climb up the grassy slope outside the cave and onto the coastal path which runs above.
CAVE ON SOUTH SIDE
Cave 1 Movie D
The entrance is about 20 ft high and 10 ft wide and it goes back about 10 ft.
Cave 2 Movie F ? a rock shelter
Cave 3 (Movies D/F )
This has a slot like entrance about 20 ft high and 10 ft wide and goes back about 30 ft. There is red slime on the walls.
Cave 4 ( Movie 10)
An entrance about 30 ft high and about 10 ft high, goes back about 70 ft, with evidence of water having reached a high level. A very clean sandy floor
Cave 5 (Movie 11 )
This is just a slot about 10 ft high going back about 4 feet.
Cave 6 (Movie 11)
This has an entrance with water in it, about 20 ft high and 10 ft wide, and goes back about 20 ft.
Cave 7 Movie 11/12 This is a through cave. The entrance is about 40 ft high and 20 ft wide and goes back into a chamber with a small passage on the left which soon closes down. The floor is rough boulders and scrambling over these you reach the second entrance or Cave 8 with an entrance 30 ft high and 20 ft wide.
Piper?s Hole (Movie 14)
An entrance about 40 ft highand 15 ft wide with pigeons nesting in it. It closes down after about 30 ft where it is about 15 ft high. The height of the passage in the cave is about 20 ft.
Movie 16 There is evidence of a cave on a small island just off the coast and on the north side of the bay but these caves are difficult of access