82 NATURAL SCIENCE [February 



The Geology of Franz Josef Land 



One of the most interesting and valuable results of the Jackson- 

 Harmsworth Expedition to Franz Josef Land is the collection of 

 rocks and fossils reported upon by Messrs E. T. Newton and 

 J. J. H. Teall in the last number of the Quarterly Journal of the 

 Geological Society (vol. liii. pp. 477-518, pis. xxxvii.-xli). All 

 the marine fossils, including some characteristic Ammonites, prove 

 the sedimentary deposits examined to be of Upper Jurassic age ; 

 and the marine strata are intimately associated with a series of 

 shales and sandstones containing plant-remains, beds of lignite, and 

 other evidences of littoral or estuarine conditions. The soft Jurassic 

 sediments seem to have been soon covered up by great flows of 

 basaltic lava, and thus preserved from destruction ; and Messrs 

 Newton and Teall allude to the curious fact, that rocks of approxi- 

 mately the same age have been preserved in exactly the same way 

 in districts so far removed from Franz Josef Land as the north-west 

 of Scotland and Abyssinia. 



The present configuration of the archipelago of Franz Josef 

 Land conclusively proves that it is formed of the fragments of an 

 old plateau. The land frequently terminates in abrupt cliffs, 

 capped with sheets of basalt which must have extended far beyond 

 their present limits. Moreover, when one compares the topography 

 of this district with that of the Faeroe Islands and the west of 

 Scotland, one is much inclined to believe that these now well- 

 separated land-areas were once continuous, and the northernmost 

 part of the Atlantic is of comparatively recent origin, as suggested 

 by Professor Suess in Natural Science four years ago (vol. ii. 1893, 

 p. 185). In any case, it is clear that the various islands of Franz 

 Josef Land were united at the time of the volcanic disturbances 

 and have subsequently been separated. The numerous raised 

 beaches on the coasts also imply comparatively recent changes of 

 level, as in many other parts of the extreme north. 



The Structure of Gold Nuggets 



The last number of the Journal of the Eoyal Society of New South 

 Wales (1897, pp. 70-79, pis. i.-xvi.) contains a beautifully illus- 

 trated paper by Prof. A. Liversidge, on tlie crystalline structure 

 of gold and platinum nuggets and gold ingots. One explanation of 

 the origin of nuggets, which has received wide acceptance, is that 

 they have been formed in situ in the gravels and alluvial deposits in 

 which they are found ; that starting with a nucleus they were 

 gradually increased in size by the successive deposits of gold from 

 solution, i.e., that they were built up of superimposed coatings 



