Ethnology of Tongareva
Stonework in Tongareva has been restricted by the lack of basalt, which precluded the manufacture of adzes and other stone implements. The field of endeavor has been confined to the use of coral and coral limestone. Coral receives the general name of punga, a name also specially applied to the softer young coral which, after being used for cooking stones, crumbles to small, whiter pieces termed tia. The harder, older coral which forms flat slabs is termed karaea. The karaea slabs were used for house foundations, for the boundaries of the religious inclosures, and for pathways over sharp coral.
Coral limestone (pae) is found plentiful on both the sea side and the lagoon side of the islands in stratified layers which cleave naturally at thicknesses of 4 to 10 inches. Limestone slabs were used for the large upright pillars around the maraes and also in some of the larger house foundations. It is curious that Lamont should have failed to recognize that the material existed abundantly in a natural state. Theorizing on the coral limestone on house sites, he stated (15, p. 159):
These remains, like the huge stones of the maraes, that are evidently made of composition, though the natives believe them to have come out of the sea, led me to believe that another race must have at one time inhabited this little portion of the globe—perhaps swept away by some catastrophe spreading destruction over their island, to be replaced by the descendants of others, thrown upon the shores in some chance canoe.
The natives' statement that the material came out of the sea could easily have been verified by Lamont. As it is, his erroneous speculation that the material was a composition manufactured by some extinct race has been accepted by subsequent writers, and the Tongarevans have been regarded as incapable of accomplishing the stonework they actually made. I have seen similar material used for maraes in Rakahanga, the Cook Islands, and Raiatea. K. P. Emory, in conversation, reports it in the Tuamotu Islands.
Tongarevan coral stonework consists of paths, wharves, fish ponds, house foundations, religious structures, and graves.