Editorial Comment. 249 
forty feet. These beds at the surface consist of red dusty soil, 
passing downwards into red, yellow or gray tuffs and compact 
pisolitic ironstone, which in turn graduates into rotten spongy 
basalt." * '■'' * As specimens of the rock vary considerably 
in structure and composition the term laterite must be taken 
to have rather a wide application. While some of the speci- 
mens are clearly tuffs, others show little trace of eruptive or- 
igin, and may be described as earthy pisolitic ironstone, more 
allied to a sedimentary formation than a volcanic. * * * The 
probable explanation of these facts appears to be that the 
greater part of the laterite is an altered basalt tuff belonging 
to the earlier basalt eruptions of the Eocene period." In 1899 
Mr. Jacquet reported that the pisolitic ironstone near Wingello 
contains free alumina, and is a variety of bauxite. Since that 
date samples have been chemically tested from many allied 
deposits, and the results show that ferruginous bauxite is dis- 
tributed over a considerable area of the colony. This ore is of 
Tertiary age, as evinced by fossil-bearing strata associated 
with it. These strata are sometimes overlain by basalt. 
The ore is composed of rounded grains of concentric struct- 
ure, and varying in size from two millimeters in diameter to 
eight centimeters. Two analyses showed respectively alumina 
thirty-four and thirty-two per cent, and iron (Fe.O,.,) twentv- 
nine and forty-four per cent; also 4.45 and 4.70 per cent of 
titanic acid. The former analysis was of an oxidized sample, 
and the latter, in each case, of an unaltered primary ore. "The 
second analysis seems to indicate that the primary ore consists 
essentially of a mixture of ilmenite and ferruginous bauxite." 
The author concludes that not only this but probably manv 
other deposits of bauxite and aluminous ores elsewhere in the 
world have been derived from alteration of basalt ; although in 
some cases not from alteration in sitn but from the distributive 
action of water in shallow lakes or rivers in Tertiary time, 
Mr. Jacquet calls attention to the somewhat similar iron 
ores of the Clealum river in Washington which have been de- 
scribed by Mr. J. P. Kimball,* and by Messrs. Smith and 
Willis, and which contain free alumina and mav perhaps be 
designated ferruginous bauxites. Messrs. Smith and Wil- 
list state: "The Clealum ore resembles in a general way some 
of the more ferruginous bauxite ores, and, as has been seen, 
• American Ohologist, 1898. xxi, pp. 161-163. 
t Trans. Am. Inst. Min. Eng., February, 1900. 
