454 E. S. Dana — Petrography of the Sandwich Islands. 



Figure 7 will give some idea of the transverse markings, 

 but details of the structure can hardly be reproduced. 



The straignter por- 

 tions of the stalactites 

 are often solid through- 

 though 



out, though here and 

 there they are hollow 

 and consist of a mere 

 shell ; often portions 

 that are perfectly solid 

 alternate with the cel- 

 lular parts, or the solid 

 parts contain a series of 

 large vesicles. Figure 

 8 gives longitudinal 

 cross sections through a 

 number of typical 

 forms. In f, the lower 

 cavity was thickly lined 

 with crystals chiefly of 

 feldspar. The exterior 

 crust is seen in the cross 

 section under the micro- 

 scope to be very thin, 

 and next to it comes 

 usually a narrow, but 

 not always continuous, band of augite with occasional iron crys- 

 tals. The solid parts contain within very slender lath-shaped 



Lava Stalactites, 



Longitudinal sections of lava stalactites in outline ( x f ) showing open and solid 

 portions, a solid and d open throughout, d with crystalline lining; the lower part 

 of /is thickly lined with crystals, chiefly feldspar. 



