258 The Ohio Journal of Science [Vol. XIX, No. 5, 



commonly scattered over the Valley. We worked at ten 

 different fumaroles of this type. In this class of fumarole the 

 highest temperature was usually at the surface of the ground, 

 rather than down six or eight feet in the throat. Because of 

 their isolation they were easier to work with than any of the 

 other kinds. 



2. Surface fissures: Continuous long lines of irregular 

 cracks and crevices, evidently formed in the roofs of lengthy 

 fissures. The surface is baked hard and is conspicuous 

 with its bright deposits and incrustations. The temperature 



Photograph by Jasper D. Say re 

 AREA 29. 

 By repeated attempts at different fissures in this line of action, we obtained a 

 maximum temperature of 329^ C. The surface of the ground 

 was icrhly colored with incrustations. 



was high and the clouds of steam of great volume. These 

 surface fissures are among the most conspicuous and abundant 

 vents in the Valley. They were often 200 yards in length. 

 Occasionally small explosion craters have been formed along the 

 fissures. These have rims of ejecta four or five feet in height 

 and ten feet or so in diameter. The steam was issuing from 

 cracks in their throats, similar to those occurring in the surface 

 of the fissure, (Example, No. 29, page 272). 



Surface fissures are the most abundant type of vents in 

 the Valley. Over half the areas which we visited were of this 

 type. Some of them were easily accessible, but, in order to 



