TE PITO TE HENUA, OK EASTER . ISLAND. 451 



lar to volcanic cinder, having the lightness and qualities of coke. In 

 some of the varieties the cavities are tilled with olivine crystals partly 

 decomposed, but generally the cavities are empty. This lava when 

 mixed with feldspar is sometimes of gray color; not unfrequeutly sev- 

 eral tints of red may be seen, though the most common is a dark, luster- 

 less brown. 



The liliaceous lavas are extremely interesting, because they form the 

 most prominent feature in the physiognomy of the island. To this 

 geological structure, with the incessant action of the trade-winds and 

 heavy rains, is due the fact that the island is surrounded by precipitous 

 cliffs, rising in some cases to a thousand feet in height. The forma- 

 tion is extremely friable, and by the action of the elements, enormous 

 masses are continually disappearing beneath the waves of the sea that 

 beat upon this unprotected shore. These tufas differ considerably in 

 consistency at the eastern end of the island. The species is a tine light- 

 red dust that is blown about by the wind and is destitute of vegetation; 

 towards the southwest end the basis is a compact mud-like red clay, 

 while the colossal crowns, intended to adorn the gigantic statues, are 

 carved out of a variety that has been scorified in one of the craters, 

 and is of a dull reddish color. 



The ordinary rules for estimating the age of rocks by compactness 

 can be applied at Easter Island only hypothetic-ally, because the seori- 

 form and more dense specimens are found immediately contiguous to 

 one another. In places they are quite conglomerated, as though older 

 formations had been disturbed by volcanic convulsions, while a new 

 flow of lava enveloped and sealed the whole into a heterogeneous mass. 

 During our short stay on the islands there was no opportunity to 

 measure the lava How or to make investigations of that nature. 



Natural caves are numerous, both on the coast-line and in the interior 

 of the island. Some of them are of undoubted antiquity and bear evi- 

 dence of having been used by the early inhabitants as dwellings and 

 as burial places. It is reported that small images, inscribed tablets, and 

 other objects of iuterest have been hidden away in such caves and 

 Anally lost through land-slides. 



The numerous hills on this island have gently sloping sides, except 

 where they approach the coast, falling at this point precipitously to the 

 sea. The plains are irregularly shaped, and some of the smaller ones 

 rise to a considerable height. The physical character of the soil is 

 alluvial. The substratum is volcanic ash and stones, and the upper 

 formation is composed of decayed vegetable matter mingled with a rich 

 deposit of decomposed lava washed down from hills by the frequent 

 rains. These plains being formed by the periodical eruptions of the 

 volcanoes, some difference may be noted in the quantity of the soil, 

 varying according to location. 



After the successive discharges of lava from the craters of Kana Ko- 



raliti aud Itaua-kao had prescribed the limits of the island and wheu 



