342 WHITMAN CROSS 
the factors used to produce three orders under the first class, 
viz.: (I) Phanerogenous (“phanerogéne’’); (II) Adelogenous 
(“adélogene”’); (111) Conglomerate. The rocks) of the first 
order are made up of definite mineral species, and their composi- 
tionis apparent. The composition of those of the second order 
is not apparent to the naked eye, and it is assumed that portions 
of them do not belong to mineral species. Further, it is stated 
that some of them are clastic; but why these are not placed in 
the third order, which is defined as containing rocks composed 
of cemented particles of older rocks, is not discussed. 
The ‘‘cabinet petrography” of the mineralogist, as Lossen 
characterized it, is still more evident in the formation of genera, 
which in the first class, embracing the largest number of rocks, 
are named after minerals. The first genus is Feldspar, includ- 
ing not only rocks consisting mainly of feldspar, but also granite, 
syenite, pegmatite, protogine, gneiss, etc. Similarly, diorite is 
a species under the genus Amphibole. Haiuy’s system has 
always been criticised as giving entirely undue weight to certain 
minerals; but unnatural as is his scheme in that respect we have 
the same idea with us today, although it is no more logical now 
than it was a hundred years ago. 
The criteria used in subdividing genera and species in Haiiy’s 
scheme are mainly those deemed of primary importance by later 
authorities. The semple and the composite are the leading heads 
under the genus, and structure is used to form varieties or modi- 
fications under the species. 
John Pinkerton, r8tz.—In 1811 there appeared in London a 
pretentious work of 1200 pages entitled: Petralogy, a Treatise 
on Rocks, by John Pinkerton, an Englishman. The author was 
an eccentric character, whose claim to. renown rests rather on 
his historical researches than on his Petralogy, for he clearly had 
little conception of the objects under discussion in that work. 
The greater part of Pinkerton’s energy was directed toa quaint 
and prolix argument against the tendency of the time to classify 
mineral substances in the same manner as animals and plants. 
His déte noire was the mineral sfectes, for he insisted that the 
