90 



H. Simotomai — Tarumai Dome in Japa'i 



to the cooling surface. The tliickness of the layers varies from 

 a few centiiiieters to half a meter. 



The sulphurous gas is still, issuiug from numerous parts 

 around the lava cliff, though it is now in minimum activity. 



The upper surface of the dome is practically flat, but it*^is so 

 rough and uneven with sharp edges, spears, and spines of yel- 

 lowish-gray lava that walking on its surface is almost impossi- 

 ble. Such slaggy, porous lava was seen everywhere around 



Fig. 2. 



Fig. 2. Tarumai before the eruption of 1909. Seen from south from 

 the coast of the Sikots Lake with the old pier in front. 



the dome at the beginning of the eruption, but now one can 

 scarcely find any on the sides, for there this phase of the lava 

 has fallen away and become buried in the talus. 



The maximum elevations are at the southwest and north- 

 east sectors on the upper surface, and between these two 

 heights a fissured zone runs from southeast to northwest. 

 Many cracks of different sizes run nearly in radial directions 

 from the center. In some cases the intervening mass between 

 pairs of the fissures is dropped down as a wedge, forming a 

 trench-depression (Graben). Many cracks are still open. These 

 features of the upper surface are like those seen on the sides 



