484 HARRY 0. WOOD 



Ordinary textures, comprising surfaces of varying character and 

 degree of vesicularity, and surface vesicle patterns, difficult to 

 illustrate or describe except at great length, but common in all 

 fields of pahoehoe. 



"Pulled" texture, seen in incipiency in the lacy texture, but 

 extended to most of the ordinary types wherever, through con- 

 tinued traction, the surface was greatly sheared after it had stiffened 

 or partially set. This gave rise to stippled and bladed surfaces, 

 and to actually fragmented surfaces, so thus, by degrees, it passed 

 over into a slaggy a-a texture. 



The textures most prevalent in the source region were the 

 pumiceous texture and the "pulled" texture. 



Slag, a product of flow made up of rough fragments varying in 

 size and in character from torn and wrapped pahoehoe crusts to 

 cindery a-a lumps. 



In a general way, here slag was characteristic of the flow 

 channels near the source and of an intermediate region down the 

 flows between the typical pahoehoe and a-a stages. 



A-a, rough-surfaced block lava, typical of by far the greater 

 part of all the 191 6 branches of flow. 



b) EJECTED PRODUCTS 



Basaltic pumice in three distinguishable varieties which, of 

 course, grade into each other: (1) a very finely vesicled variety of 

 light-yellow color, almost a thread-lace scoria in structure; (2) 

 ordinary yellow to brown basaltic pumice, with fused surfaces, 

 resembling pulled molasses candy; and (3) a more coarsely vesicu- 

 lated brown to black pumice which grades with the increasing size 

 and the decreasing numbers of vesicles into 



Cinder lumps, which, in turn, grade with decreasing vesicularity 

 and increasing density into 



Slag lumps, (1) some of which exhibit a surface like obsidian; 

 (2) others a surface like a-a. 



All these were observed all along the rift and about the spatter 

 cones, but the pumice phases were very abundant near the south 



