Parking is at S 38° 15.682 E 174° 53.940
35 million years ago these oysters lived, as you would expect, in the sea. Yet today they are now 17 kilometres from the sea. Once this whole area lay under sea. All these years ago, large parts of the King Country and Waitomo area as far south west as Awakino and south east to Benneydale were under water. The picture below shows the location of the oyster beds in relation to the present day coastlines and towns.
The coastline was wild and wind swept with huge beds of oysters. Gradually sediment and shell fragments smothered the beds compacting to form limestone. About 10 million years ago, movement in the earths crust caused the sea floor (along with the limestone encrusted oyster beds) to rise and become land. In places wind and water have eroded the limestone and exposed the oysters.
The photo below shows the limestone with the oysters clearly visible. The giant oysters are likely to be Flemingostrea wollastoni. Similar giant oysters were found beneath the limestone at Port Waikato. In addition to the oysters, others chips of barnacles, bryozoans, bivalves, and some red algal grains were also found in the limestone.
These oysters can also be viewed in the Piripiri Caves which are 4km further on from the Natural Bridge. These caves are not guided so you will need a torch, good boots, and mud-proof clothes.
Once you complete the following EarthCache requirements you can post your find without delay, as per the EarthCache guidelines. You will also need to verify your find by sending us a message with your answers to these questions and we will answer in due course:
1. Use the text "Mangapohue Oyster Beds - GC22XN6" in your email.
2. The published co-ords will take you to an information sign. What is the altitude here? (UPDATE: April 2014, sign missing but you can still answer this question).
3. Approximately 6 metres away is an excellent example of an oyster encrusted in the limestone. Describe the size of this oyster.
Please DO NOT post answers with your log .