MAN MADE STUFF

DRESSED BEACH ROCK AT NU'ALOLO-KAI
NA PALI, KAUA'I

by
William K. Kikuchi

 

Introduction

The tradition of using stone for construction is ubiquitous among the cultures of the world. This tradition generally is divided among those that use unaltered stone and those that use dressed stone. Alteration or dressing refers to the shaping of natural stone by a human agency. Any surface which is retouched, ground, flaked or pecked, either on one surface or all surfaces, is regarded as altered or dressed. These stones are then used in the construction of man made features such as walls, temples, kerbings, house sites, etc.

Hawaiian Islands

As far as the author knows, only two islands within the Hawaiian Islands have reported the occurrence of worked stone. These are the islands of Hawai'i and Kaua'i. It is very probable that the other islands have dressed stone but that they are yet unreported.

On the Island of Hawai'i, dressed stone was reported from the site of an unnamed temple at Kukuipahu  located in the district of North Kohala and in the ahupua'a of Kukuipahu. This large temple was mapped by the State of Hawai'i sometime in 1971 or 1972, and the subsequently vast amounts of dressed stone were reported. Two types of dressed stones were recorded: the first was the common basalt stones of which 65 were counted; the second was the larger red tufa stones 11 of which were noted on the survey map. The stones and the temple are reminiscent of the temples of the Society and the Marquesas Islands.

On the Island of Kaua'i, dressed stones are found in principally two sites.

The first of these sites is the Kikiaola aqueduct [Kiki-a-Ola] located in Waimea Valley in the district of Waimea. This site is now called the Menehune Ditch because of its legend relating to the menehune as its builder. The ditch is reinforced by a wall of dressed, vesicular basalt stones, originally believed to have been around 12 feet high and over 200 feet in length. Today, the wall has been nearly covered by a road. The only portion that remains visible is an approximately 100 foot long alignment of the top two stones of the wall.

The second site on Kaua'i can be found at Holoholoku, or the royal birthplace in Wailua, District of Lihu'e. This site contains a large, single slab of beach rock that served as a step into the birth house. The slab is worked on its sides and top surface, and indications from the site area suggest that the stone was worked at the site, as pieces of the beach rock can be seen in the soil. The stone was exposed in the 1920s by the excavation supervised by Kenneth P. Emory (Bishop Museum ) and the Kaua'i Historical Society. Previous to the 1920s the entire area was covered with a talus of soil from the surrounding hillside. Beneath the large slab of stone, a small grave was found with the body of an articulated dog (K. P. Emory, personal communication).

Nu'alolo-Kai, Na pali, Kaua'i

The valley of Nu'alolo-kai, located on the Na pali coast of the island of Kaua'i is a large marine eroded valley. The valley is bounded on three sides by a sheer cliff and a large talus of broken stones. The seaward and northern facing part of the valley is at sea level and composed primarily of marine deposited detritus of coral, marine shells and calcareous sand. The shore off this valley consists of a shallow but extensive reef of live coral. The reef extends nearly 200-300 feet from the shore and at low tides is almost completely exposed. The beach is composed of large water worn cobbles, sandy spots and at the center a large beach rock shelf. It is this beach rock shelf that is the topic of this paper.

Beach Rock

The beach rock commonly found on many of the Hawaiian islands:

The beach rock of Nu'alolo-kai was composed of calcareous sand grains, small fragments of marine shell and minor amounts of basaltic material. Each grain was cemented together by the mineral calcite. According to a study by Emery and Cox ( 1956:384) the hardness of beach rock decreases as the depth of the stratified bed increases. This is due to the decreasing penetration and saturation of the mineral calcite which is in solution form. The calcite or calcium carbonate is in dissolved form within the seawater. As the waves keep saturating the exposed beach rock with the seawater, the calcium carbonate will seep into the minute crevices, filling as well as dissolving other material. Thus the thicker the beach rock bed, the softer and less cemented the stratified boundaries between beds become, and eventually hairline cracks will be formed horizontal to the plane of the beds.


The force of ocean waves can crack these beds and move the pieces or boulders around the shoreline. beach rock is almost always seen as slabs of rock exhibiting two parallel surfaces. This feature meant that beach rock was ideally suited for the construction of walls, kerbings and house sites, as little work was needed to dress the stone to the desired shape. Often the stone was left undressed, the desired feature for construction being only the two natural parallel surfaces as facing.

SURVEY

While exploring the reaches of the valley, a curious thing was noted. That was the occurrence of many scattered slabs of beach rock, some with definite squared off sides. Scattered on the beach were several slabs of beach rock, some large and others the size of small boulders. While exploring the reef area during days of low tide, we noted another curiosity, namely that the reef was pretty much flat and had very few open crevices and holes. A few large beach rock slabs were seen on the reef, but upon closer inspection, they always seemed to be associated with a nearby depression in the reef. One or two reef depressions still had a beach rock within them. These slabs were placed in such a way that the two parallel surfaces of the beach rock were horizontally laid such that one face was nearly level with the reef's surface.

The beach rock nearly filled the sizable depressions, making their surface, level with the surrounding reef. The beach rock had to have been dressed in order to fit the depressions. These were not perfect fits but a commendable job was done anyway. It was then that I realized that perhaps the dressing of some of the beach rock was intentionally done to allow people to walk on the reef without falling into the depressions. In the instances where the beach rock lay on the reef and adjacent to the depressions, one of two explanations may apply. The first was that the beach rock had not yet been dressed and made ready to be placed in the holes. Or perhaps the tsunami of 1946 had lifted these rocks out and deposited them nearby.

On the shore and toward the terraced sites of K2, K3, K4 and K5 were many slabs of beach rock, some naturally shaped and others suggesting some minor dressing. These were used in the construction of house kerbings, wall slabs and, in one case, to cover a crypt. Even an ancient kerbed and paved walk along the shore showed signs of dressed beach rock in its construction.

Back of the shore we found large slabs of beach rock strewn about, the lack of order to their distribution suggesting that they had been moved about by a tsunami. Because beach rock is very common and readily available, it was used extensively in all construction within Nualolo-kai, commonly with basalt stones.

Ten beach rock slabs on the shore were measured.

01. 20 x 16 1/2 x 7 in., house site on shore flat
02. 28 x 17 x 4 1/2 in , house site on shore flat
03. 18 x 19 x 7 in., house site on shore flat
04. 32 x 28 x 5 in., shore
05. 60 x 34 x 8 in., shore
06. 56 x 32 x 13 in., shore
07. 36 x 23 x 8 in., shore
08. 70 x 35 x 10 in., shore
09. 46 x 35 x 11 in., shore
10. 43 x 41 x 10 in., shore


These slabs of what seemed to be worked beach rock were relatively thin. From the above listing we see that the thickness ranged from 13 inches to 4 1/2 inches, which probably signifies the thickness of the stratum.

Mining

The large outcropping of beach rock in the central portion of Nualolo-kai was the source of the stones used for construction. The bedding faces of the beach rock were the weakest part of the stone. Natural fractures always ran horizontal to the bedding faces and with a wooden lever these slabs could be easily separated. The slabs, once moved, could be pecked or hit with basalt hammer stones to crack them into smaller pieces . The dressing could be done at the site or at the quarry. The distance to the sites from the outcrop is approximately 100 yards.