iv CONTENTS. 
NUMBER CLVIUI. 
Art. XII.—Examination of Mr. Alfred R. Wallace’s Modifi- 
cation of the Phys ry Theory of Secular Changes of 
asthe oy 3. CRONG, A 6 oe 2 5 8 a a 
UL. Ee ig tation ‘teak the U. 8. Geological Survey, 
Rocky Mountain division.—V. On Sa rare ete., in the 
Nevadite of Chalk Mountain, Colona: by W. Cross. 94 
—Occurrence of the Lower Burlington Limestone in 
a Mexico; by F. Sprincr 7 
Page 
e Minnesota Valley in the Ice Age; by W. bara 104, 
Xvi_ch hoi Drift in Montana and Dakota ; by C. 
Wut 
nbs Giawal and Champlain Periods about the mouth of 
e Connecticut Valley—that is, in the New Haven © 
rae y J. D. Dana. (With Plates I and II)_--- 118 
XVII. —-Supplement to Paper on the “ Paramorphic Origin 
of the Hornblende of the Cry ‘acallinie Rocks of the North- 
western States; by R. D. Irvine 
.—On Herderite (?), a glucinum calcium phosphate and 
fluoride, from Ostend County, Maine; by W. E. HippEen 
and J. B. N 
XX.—Dec ay of f Rocks in Brazil ; by O. As Derpy...._.- ee 
XXI.—Principal Characters of American Jurassic Dinosaurs; 
by O. ARSH. Part On the Diplodocide, a new 
family of the Sauropoda. (With Plates III and IV).. 162 
SCIENTIFIC INTELLIGENCE, 
themistry and Physics.—Perfect Elasticity - ne AE sm ra bodies, 
SPRING, 140.—Nitrogen selenide, BER 
: Hyponitrous acid 
and silver hyponitrite, BERTHELOT and Dar 14i Cert ain new maeapinsatte 
of Silver, PoLeck and TatiMMEL, 142.—Velocity of Sound in Air, J 
BLAIKLEY, 143.—The Condensation of Aqueous V 
uree 
spheric Tt Red Sunsets, 144.-—Physical Studies of Lake Tahoe, J 
LeConte, 145. 
se Mineralogy. —Geology of Wisconsin, Survey of 1873-79, T. C. 
f the Susqueha sone i iver region in the six 
awanna, Luzern e, Columbia, Montour and Northum- 
f , 149.—Da a E. Suess, 151.—Uncon- 
formability between the Upper and Lo ilurian ions i 
G. H. Cook: G 0 ) explored and mapped by Dr. 
. V. Hayden, 1869 to 1880: Emeralds from North Carolina, G. F. Kunz, 153. 
—Tourmaline from oe Main 
oF, uRY: Illustrated 
ear att — of Gre ape Vin se a ce Beas isiveal, Busu & 
nine ee zea Law - Heredity: A Study of the Cause of Variation 
an . Br 
Origin oe Living Organisms, W. OOKS, 156. Aone phy on ‘the | 
results of dredging onda | the supervision i 
sol 
8. re Mivtmr, 158,—The 
Miscellaneous Sotentifia Ite Mclen proposed Conference of Electricians at 
Philadelphia: Bust of Liebig, 1 ies 
Obituary.—General ANDREW A. aie 160, 
