146 NATURAL HISTORY OF HAWAII. 



otherwise have clone — a course well illustrated by the summit crater on ^Manna 

 Kea. 



The Floor of the Crater. 



The floor of tlie crater is well covered with cinders, scoria and sand, its sur- 

 face being- relicvetl by the cones previously mentioned. From these craters the 

 loose material forming them, and that covering the floor of the great crater en- 

 closing Iheiii. was ei-ui)le(l. The light, loose material in the crater has a reddish 

 tinge often varied with black, grey, yellowish-broA\n and red and shows no 

 mark of its exact age. Toward the extreme eastern end there is an old pahoehoe 

 How, and higli up nn Itic eastern wall two flows of aa have broken forth. Conrsing 

 down llie side wall, they have pushed their wa^' some distance out over the flo(n' 

 of the crater. 



Although the walls of the crater are steep it is possible to descend them 

 almost anywhere. The descent is made easier on acconnt of the sand and cinders 

 that ]ia\(' l)cen heaped up at the foot of the clififs on all sides. The floor and 

 inner walls of the crater are of great interest to gfeologists and will well repay 

 a visit. For the toui'ist, the "bottomless pit," a remarkable l)low-h()le; Pele's 

 l*ig-pen, a small partly-filled crater; the Chimney; the Crystal Cave; and the 

 chain of four craters known as the Natural Bridge, lying along a crack in the 

 floor of the crater, are natui'al objects Avell worth inspection at fli'st hand, and 

 interesting enough to tempt many to make the scramble down into the crater. 



The summit of the mountain and its crater is a barren waste only relieved 

 here and there by a few plants, among them the remarkable plant known as the 

 silver sword, which is elsewhere described. 



The PIistory of Haleakala. 



Geologists agree that the history of Haleakala is a complicated one in which 

 the formation of the mountain by the nsual processes of summit eruptions and 

 surTace Hows have played dominant parts throngh long ages. The fracture 

 of the mountain that opened the great discharge ways at either end of the crater 

 must have occui-red as the mountain Avas nearing completion. The simultaneous 

 discharge of lava by l)oth of these great openings in the crater wall is proven 

 by the similai-ity of the lava found in the gaps themselves and in the floor of 

 the cratei- from end to end. 



As the life of the mountain as a living volcano neared its close, it appears 

 that the convulsions which split the pile to its foundation brought about the 

 appreciable sinking of tlie extreme eastei-n portion of the dome. The final flows 

 from the gaps at either end of the crater reunited the fracture in the founda- 

 tion, filled the subterranean chambers formed by earlier flows, and left the 

 crater a solid mountain v,ith its interior completely filled with the rock mr.terial 

 that makes up its huge bulk. The expiring fires, through minor fissures in the 

 last-formed crater floor, threw up the numerous cinder cones scattered over it. 



