348 
Porphyrites, xiv., 203 
Porphyritic gneiss, viii., 49 
Porphyry, i., 19, 49; ii., 94; viii., 
162 
in Colorado, v., 122, 124, 126, 127 
of St. John, xiv., 196 
syenites, v., 220 
Port Kent and Ausable Chasm, xyv., 
21 
Portraits of Priestley, viii., 17-20 
Portulaca parvula, vii., 8 
Postage on natural history speci- 
mens, xlil., 122 
Post, Dr. A. C., death of, v., 280 
Post, George B., elected resident 
member, xiy., 154 
Potassium, v,, 187 
chlorate of, v., 215 
hydroxide of, yv., 193 
peroxide of, v., 214-215 
Potash brine, analysis of, ix., 41 
Potentilla rivalis, var. millograna, 
MAU 
subviscosa, vili., 80 
Thurberi, viii., 78 
Pothocites Grantoni, iii., 40 
Pot-hole, ix., 3 
Pot-holes, x., 8 
near Williamsbridge, N. Y., i., 
181-183 
“* Potomac’? clays, v., 136 
group, geological age, etc., x., 36 
Potsdam rocks of S. E. Penn., viii., 
48, 50, 51 
sandstone, figures on, iv., 42 
strata, v., 216, 217 
Poulton, Prof. Edward, elected cor- 
responding member, xiil., 171 
Powder-mill Creek meteorite, vi., 
161, 162 
Praseodymium, v., 184, 200 
Pre-Cambrian and Post-Ordovician 
trap dikes in the Adirondacks, 
xv., 248 
Introduction, xv., 248 
Present Rock Classification, xv. ,248 
Proposed Change in the Classifica- 
tion, xv., 249 
The Dikes, xv., 249 
Description, xv., 249 
Distribution, xv., 250 
Scarcity north of the Adiron- 
dacks, xv., 251 
Summary, xv., 252 
INDEX. 
poe ee classification of, xiv., 
95. 
topography of the Adirondacks, 
xv., 189 
upper limit of, xiv, 194 
volcanic rocks, xiv, 189 
Precious stones of North America, 
viii., 160 
Precipitation, to purify water, vi., 
52, 53 
Preglacial drift, vi., 16-18; viii., 179 
of New Jersey and Staten Island, 
iv., 26; glacial drift, iv., 30 
Prehistoric man in America, v., 120 
races of America, skill of, iii., 15 
Prehnite, 11., 88; viil., 2; ix., 141 
new locality, v., 80 
Preliminary notes in meteorite, v., 
231 
Preservation of building materials, 
etc., v., 56-71 ; 
of building stone, v., 13 
of organic tissue, v., 117 
of wood, v., 116-120 
of stone, artificial, ii., 77, 78 
Prevention of tubercular disease, i., 
181 
Price of the Transactions, x., 1 
Priestley, Dr. Jos., decease, ii., 111 
likenesses of, viii., 17-20 
“Lunar Society,’’ associates of, 
Vili., 23, 24 
Primary Matter, v., 184 
Prime, Mr. Rufus, vi., 41 
Primitia aurora, oculata, fusiformis, 
Xiv., 186; 157 
Primitive education, xv., 155 
Primula parryi, i., 8; viii., 78 
Prince, J. Dyneley, xv., 147 
Principal lines of disturbance in cer- 
tain portions of Atlantic Coastal 
Plain, xiv., 9 
Problems about to confront astrono- 
mers of the Twentieth Century, 
xv., 146 
Proboscidia, iv., 19, 20 
Proccedings, American Association 
for the Advancement of Science, 
Tbs, 
Process for amalgamation of silver 
ores, ili., 1, 2 
Process of cutting intaglios and 
cameos, iii., 105 
Prochlorite, vi., 130 
