164 Revieips — Dr. Tempest Anderson — Volcanic Studies. 



it rises beneath the ice-sheet of the Vatna Jokul, and after running 

 through the terrible waste of the Myvatn's Oroefi, finally discharges 

 as a regular glacier river into the Asar Fjord on the north. In 

 pi. L, a more specialized section is given, where the same river 

 is seen plunging into a canon about 400 feet deep, cut in the 

 columnar basalt. The author again points out that the separate 

 layers observed here need not in all cases represent a different 

 eruption, and he refers to his remarks on the Jaujac section 

 (pi. xxxviii) as applicable in this case. At the northern end of the 

 jokulsa gorge some remarkable volcanic structures are exhibited 

 as the result of the injection of basaltic lava into volcanic ash 

 (pis, lii and liii). 



One other subject in connection with the copious illustration of 

 Icelandic phenomena must sufiice — we refer to the fissures termed 

 Gjas, due to the unequal settlement of the lava-crusts on cooling. 

 These seem well developed in the Keykjaues peninsula, and are 

 partly due to the formation of tunnels, whereby the still liquid lava 

 continues to flow after the surface has consolidated. The mouth 

 of one of these old tunnels is shown as a lava-cava at Myvatn 

 (pi. Ixxii). The celebrated Almannagja in the valley of the Oxera 

 is an instance of a Gja (pi. Iviii), and this has all the appearance 

 of a road hollowed out between a cliff and its undercliff. But the 

 most interesting series of Gjas, from an historic point of view, are 

 those which surround the Logberg, on which the Icelandic 

 Parliament met at Thingvalla. The half-plate, No. Ixi, shows us 

 this curious rock table, held up in a fork between two faults and 

 almost surrounded by deep Gjas, full of water, fresh, clean, and 

 running — a nice place to cool the ardour of an obstreperous 

 legislator ! 



There are many interesting photographs from well-known volcanic 

 regions on the west side of the North American continent ; and the 

 author, as we have already noted, has just had time to add five very 

 graphic pictures of the recent West Indian eruptions. We trust, 

 however, that we have already indicated sufficient to give a general 

 idea of the work, which has been a labour of love, occupying the 

 author's spare time for the last eighteen years. In this work art and 

 science are happily combined, so that our gesthetic tastes are gratified, 

 whilst we are receiving instruction in the mechanism of volcanic 

 action, past and present. May we not say that the author and 

 photographer has realized the Omne tulit punctum qui miscuit utile 

 dulci of the Latin poet ? 



Whilst expressing our admiration of this work we must draw 

 attention to a passage on page x of the preface, where the author 

 states " that the mere enumeration of books and papers on 

 Vesuvius and the other South Italian volcanoes occupies 340 quarto 

 pages of a Report of the Geologists' Association." Apart from the 

 inherent improbability of a mere list of the literature of the subject 

 occupying 340 quarto pages, we are in a j)osition to state that the 

 present librarian of the Geologists' Association knows nothing of any 

 such report. W. H. H. 



