312 The American Geologist. May, 1900 
parison of these two "theories of the earth," especially con- 
sidering in the latter case (the meteoritic), the argument urged 
by Prof. Chamberlin, and concludes, we are at one with him 
in thinking that an earth of heterogeneous constitution, prog- 
ressively reorganizing itself, would give larger possibilities of 
internal shrinkage and that the shrinkage must be deep seated 
as well as superficial. e. w. c. 
Nepheline Melilite Bas.alt from Oahu, Hawaiian 
Islands. 
In 1875 Wichman describeda Nepheline Melilite bearing 
rock found by him among ballast brought by a vessel to Ham- 
burg from Oahu, Hawaiian islands.* Later the same rock 
from an equalh' indefinite source was described by Cohenf 
and again by Stelzner.J Rosenbusch§ also makes mention 
of it in his textbooks. So far as is known to the writer the 
exact source of the rock thus described has remained un- 
known up to the present time. Indeed the work of Dana|| 
tended to throw a doubt upon the occurrence of the rock in 
place upon the island at all, and left petrographers wholly 
in the dark as to the sources of the ballast material described. 
When, therefore, in 1899, professor C. H. Hitchcock, of 
Hanover, New Hampshire, informed the writer that he was 
to visit the island and offered to make collections for the 
National Museum, it was at once suggested that among other 
things he collect as full a suit of the rocks as occasion would 
permit. This was accordingl)' done, and it is interesting to 
note among the samples, which are mainly ordinary basalts, 
some beautifully fresh, dark gray, sometimes almost holo- 
crystalline rocks, bearing nepheline, melilite, olivine and 
p}roxene, with abundant iron ores and perofskite as their 
chief constituents. The main source of these rocks is given 
and the Moiliile quarr\-, the la\"a of which evidently came 
from the Rock}- Hill craters.^ Clefts in the rock are cov- 
*\eues Jahrb., 1875, p. 172. 
tibid., 1880, II, p. 55. 
Jlbid., 1882, I, p. 229. 
§See Fig. 6, pi. XV, Mikros Physiographie 2nd Ed., Vol. I, 1885. 
II Am. Jour. Sci.. Vol. 37, 1889, p. 44.1. 
■"See Hitchcock, Geol. of Oahu, Bull. Geol . Soc. of Am., Vol. 1 1, 1900 
p. 46. 
