TRACHYTE ON THE ISLAND OF HAWAII 



511 



Near the northern base of Mount Hualalai is a tuff cone, notably 

 larger than those on the upper slopes of the mountain, and forming a 

 very striking feature of the landscape as seen from the north. This 

 cone, called Puu Waawaa, seems at first, like many others, an excres- 



FiG. I. — Map of a portion of the island of Hawaii. 

 (From map issued by Hawaiian Government Survey.) 



cence on the surface of the larger volcano, but the material of which 

 it is made is the trachytic lava to be described, and it is a matter for 

 future observation to determine whether the situation relative to 

 Mount Hualalai is not, as the writer suspects, quite a matter of 

 chance. The base of Puu Waawaa is at about 3,300 feet above the 

 sea and its summit several hundred feet higher. Adjacent to the 

 cone of Puu Waawaa on the north, and extending west of north for 



