VI 
CONTENTS 
PAGE 
Density of Radio-Lead from Pure Norvegian Cleveite.. 
By T. W. Richards and C. Wadsworth, 3d. 505 
The Action of Alkali in the Production of Lipolytically Active Protein .... 
By K. George Falk 557 
Steric PIindrance and the Existence of Odd Molecules (Free Radicals) 
By Gilbert N. Lewis 586 
The Cobaltammines By William D. Harkins, R. E. Hall and W. A. Roberts 598 
The Equilibrium Between Acids and Bases in Sea Water 
By Lawrence J. Henderson and Edwin J. Cohn 608 
Electrical Conduction in Dilute Amalgams 
By Gilbert N. Lewis and Thomas B. Hine 634 
The Osmotic Pressure and Lowering of the Freezing-Point of Mixtures of Salts 
with One Another and with Non-Electrolytes in Aqueous Solutions 
By William D. Hawkins, R. E. Hall, and W. A. Roberts 642 
Further Study of the Atomic Weight of Lead of Radioactive Origin 
By Theodore W. Richards and Charles Wadsworth, 3d 694 
A Revision of the Atomic Weight of Tin 
By Gregory Paul Baxter and Howard Warner Starkweather 718 
GEOLOGY AND PALEONTOLOGY 
PACK 
Sub-Marine Solution of Limestone in Relation to the Murray-Agassiz Theory 
of Coral Atolls By Alfred Goldsborough Mayer 28 
The Extension of the Montana Phosphate Deposits Northward into Canada 
By Frank D. Adams and W. J. Dick 62 
The Results of Investigations of the Ecology of the Floridian and Bahaman 
Shoal-Water Corals By Thomas Wayland Vaughan 95 
Cambrian Trilobites By Charles D. Walcott 101 
The Mechanics of Intrusion of the Black Hills (S. D.) Pre-Cambrian Granite 
By Sidney Paige 113 
On the Fossil Algae of the Petroleum- Yielding Shales of the Green River 
Formation of Colorado and Utah By Charles A. Davis 114 
Banded Glacial Slates of Permo-Carboniferous Age, Showing Possible Seasonal 
Variations in Deposition By Robert W. Sayles 167 
Geographic History of the San Juan Mountains Since the Close of the Meso- 
zoic Era By Wallace W. Atwood and Kirtley F. Mather 177 
The Age of the Middle Atlantic Coast Upper Cretaceous Deposits 
By W. B. Clark, E. W. Berry, and J. A. Gardner 181 
Upper Cretaceous Floras of the World By Edward W. Berry 185 
Preliminary Report Upon the Possibility of Controlling the Land Slides Ad- 
jacent TO the Panama Canal 193 
On THE Presence of a Median Eye in Trilobites By Riidolph Ruedemann 234 
Clift Islands in the Coral Seas By W. M. Davis 284 
The Exploration of the Pacific By W. M. Davis 391 
The Importance of Gravity Observations at Sea on the Pacific 
By John F. Hayjord 394 
The Problem of Continental Fracturing and Diastrophism in Oceanica 
By Charles Schuchert 407 
In Relation to the Extent of Knowledge Concerning the Oceanography of 
the Pacific By G.W. Littlehaies 419 
On the Distribution of Pacific Invertebrates By Wm. H. Dall 424 
Mid-Pacific Land Snail Faunas By H. A. Pilsbry 429 
