Geology and Natural History. 73 
microscopically, and all the points are discussed with admirable 
thoroughness. The remarkable disintegration which has reduced 
many of the seemingly solid masses of iron to a fine powder, Dr. 
Smith attributes first to the loss of moisture, which results in the 
production of cracks in the surface, and then to the fact that the 
Fe Ni Co Cu 1 C (combined). 
93°16 2°01 0°80 0°12 0°32 0°41 0°02 2°34=—99°18 
and t. sociated with the iron in the dolerite were the 
following minerals: niccoliferous pyrrhotite, graphite, hisingerite, 
magnetite, spinel a . Of these the graphite is the 
Smith for this extensive occurrence of native iron. He argues 
that the basaltic rocks of Northern Greenland at the time of their 
eruption must have forced their way through lignitic miocene 
beds, setting free by their heat vast amounts of gaseous hydro- 
carbons, which would have exerted a powerful reducing effect on 
gated some of the other so-called meteoric irons of Greenland, 
found at various localities for lat. N. 63° to 76°. He concludes 
that they are all similar to the Ofivak iron, and probably, like it, 
fills cavities formed from the oxidation of pyrite. Fine trans- 
re 
Scopic, are alternated with cryptoerystalline masses, In which, 
Occasionally, are seen small brilliant particles of gold. The 
Vulture vein is enclosed in walls of a schistose gneiss or mica 
schist, and the atmospheric spent seine of the sulphide has 
been so complete that at a depth of nearly 300 feet only cubical 
cavities and a curious structure due to t : te 
are observed, and the mine at that considerable depth is com- 
pletely dry. B.S. 
6. The ‘Botanical Text-book. (Siath edition.) Part I. Strue- 
tural Botany, or Organography on the basis of Morphology. To 
