86 



Couthouy on Coral Formations 



The gorge, which in this instance may possibly have been formed by the 

 recession of the falls, extends almost three-fourlhs of a mile, and then gradu- 

 ally widens into a common valley, terminating seaward in a broad plain. 



SECTIONS OF THE RAVINE AT THE FALL OF VAINAFA. 



At Hilo, on the Island of Hawaii, there is a very beautiful 

 miniature ravine of this class, at the cascade of Waianuenue, 

 (" the water of the rainbow,") and there are grand examples 

 of it in the falls of Wailua and Hanapepe in the island of 

 Kauai, especially in the latter, which pitch down full five 

 hundred feet, into a circular basin about one thousand feet 

 round, hemmed in by walls of alternately columnar and strati- 

 fied lava, the only break in which is the narrow outlet for the 

 stream. If we imagine the rapids of Lake Erie to be a plain, 

 girt with lofty mountains, with the Niagara flowing through it, 

 and this latter narrowed below the falls to one-fourth its pres- 

 ent width, we shall have a very good idea of the ravine under 

 consideration. Of those similar in form, but having no stream 

 of water, there is a fine exemplification in the great amphi- 

 theatre at the head of the Nuuanu valley, in Oahu. They 

 are also to be seen in full perfection, on the north side of the 

 ridge of Konahuanui, between the Pali, or precipice of 

 Nuuanu, and Kualoa. There is one near Waiahole, described 

 by the late Meredith Gairdner, M. D. (in a " Sketch of Oahu," 



