24 WM. H. HOBBS 
In conclusion, I would suggest to all persons publishing 
analyses of rocks the advisability of printing beneath the figures 
showing the percentage, composition, the corresponding molec- 
ular ratios, and further, that the arrangement of oxides in the 
analysis be for the sake of uniformity that which has been con- 
sistently followed by Rosenbusch, Washington, and some others, 
and which is here used in the composite tables showing the 
averaging of analyses for the composite diagrams. The princi- 
pal deviation from this order which I have observed is an inver- 
sion of the order of magnesia and lime or of soda and potash, 
which can hardly be regarded as essential. If these suggestions 
be followed, the work of those who examine rock analyses will 
be materially lightened and the liability to error in transcribing 
will be lessened. 
WitiiAM H. Hosss. 
UNIVERSITY OF WISCONSIN, 
Madison, Wis. 
ROCKS WHOSE ANALYSES HAVE BEEN COMBINED TO PRODUCE 
THE COMPOSITES OF THE GRANITIC-TEXTURED IGNEOUS 
ROCKS 
The greater number of the analyses of these rocks are to be found either 
in the tables of Rosenbusch’s Elemente der Gesteinslehre, published in 1898 
(abbreviation R), or in Clarke and Hillebrand’s Azalyses of Rocks and Ana- 
lytical Methods, published in 1897 (abbreviation C and H). 
GRANITE ” 
. Alkali-granite, Drammen, Norway. 
. Alkali-granite, Sandsvar, Gu 
Alkali-granite, Pelvoux, Dauphinée, France. 
. Alkali-granite, Hardwick quarry, Quincy, Mass., Am. Jour. Sci. (4), 6, 
p. 181. 
5. Alkali-granite, Montello, Wis., Hobbs and Leith. To be described in a 
forthcoming bulletin of the Geol. and Nat. Hist. Survey of Wisconsin. 
6. Alkali-granite, Waushara Co., Wis., Bull. No. 3, Wis. Geol. and Nat. 
History Survey, 1898, p. 2. 
. Muscovite-biotite granite, Hautzenberg, Bayerischer Wald, Germany. 
. Muscovite-biotite granite, Katzenfels, Graslitz, Erzgebirge, Bohemia. 
FW nN 
coomM 
t Bull. 148, U. S. Geol. Surv. 
2 All the granite analyses with the exception of certain of the alkali granites are 
selected from Rosenbusch’s list, on page 78 of the work cited. 
