D. K. n.\'ii)i:NSK. Sei.sk.Skr., natlmv. oc, math.Aid. \'III.4 [Th.Thoukf.i.sson] 



Plate IX 



ft 



■ .i,':: >-..;r . '.K-r ■ ' 



a. Hveragerùi at Reykjafoss, looking noiUi. Onh' the alkaline springs in tlie noitlicrn part 



of Hverageröi are visible. 



6. A mud volcano at Hengill. The rod shown is about 1 ni. high. 



