--EART* 

 SCIENCI 

 UBRARt 



THE JOHNS HOPKINS UNIVERSITY CIRCULAR, No. 293 



MARCH, 1917 



GECvLOGY : * 



CONTENTS 



PAGE 



* .'Gfeofrgicat Surveys Vith Special Reference to the Work of the Maryland Geo- 

 . * jlggjg^l.'Survty*. W. B. CLARK 



3 



The Use of Average Analyses in Defining Igneous Rocks. E. B. MATHEWS. ... 12 



The Delta Character of the Tuscaloosa Formation. E. W. BERRY ......... 18 



The Role of Mineralizers in Ore Segregations in Basic Igneous Rocks. J. T. 



SINGEWALD, JR ................................................... 24 



The Environment of the Tertiary Marine Faunas of the Atlantic Coastal Plain. 



J. A. GARDNER ................................................... 36 



The Pelecypods of the Bowden Fauna. W. P. WOODRING ................... 44 



Origin of the Natural Brines of Oil Fields. F. REEVES ................... 57 



An Upper Cretaceous Seacoast in Montana. W. T. THOM, JR ............. 68 



A Remarkable Upper Cretaceous Fauna from Tennessee. B. WADE ......... 73 



The Occurrence of the Tuscaloosa Formation as Far North as Kentucky. 



B. WADE ........................................................ 102 



The Habitat of Belemnitella Americana and Mucronata, G. E. DORSET ...... 107 



PLANT PHYSIOLOGY: 



The Department of Plant Physiology. B. E. LIVINGSTON ................. 133 



Publications from the Laboratory of Plant Physiology, 1909-1917 ......... 154 



Atmometric Units. B. E. LIVINGSTON ................................... 160 



The Vapor Tension Deficit as an Index of the Moisture Condition of the Air. 



B. E. LIVINGSTON ............................................ ..... 170 



Incipient Drying and Temporary and Permanent Wilting of Plants, as 



Related to External and Internal Conditions. B. E. LIVINGSTON ........ 176 



The Effect of Deficient Soil Oxygen on the Roots of Higher Plants. B. E. 



LIVINGSTON and E. E. FREE ....................................... 182 



The Experimental Determination of a Dynamic Soil-Moisture Minimum. H. 



E. PULLING ................................................... . . 186 



Some Unusual Features of a *Sub- Artie Soil. H. E. PULLING ............. 188 



The Geographical Distribution of the Citrus Diseases, Melanose and Stem-end 



Rot. H. S. FAWCETT ............................................. 190 



Preliminary Note on the Relation of Temperature to the Growth of Certain 



Parasitic Fungi in Cultures. H. S. FAWCETT ....................... 193 



Symptoms of Poisoning by Certain Elements, in Pelargonium and Other 



Plants. E. E. FREE .............................................. 195 



The Effect of Aeration on the Growth of Buckwheat in Water-Cultures. E. E. 



FREE ..... ....................................................... 198 



The Effects of Certain Mineral Poisons on Young Wheat Plants in Three-Salt 



Nutrient Solutions. E. E. FREE and S. F. TRELEASE ................. 199 



Leaf-Product as an Index of Growth in Soy-Bean. F. M. HILDEBRANDT ..... 202 



A Method for Approximating Sunshine Intensity from Ocular Observations of 



Cloudiness. F. M. HILDEBRANDT ................................... 205 



Moisture Equilibrium in Pots of Soil Equipped with Auto-Irrigators. F. S. 



HOLMES ......................................................... 208 



Seasonal Variations in the Growth-Rates of Buckwheat Plants under Green- 



house Conditions. E. S. JOHNSTON ................................. 211 



On the Relation of Chlorine to Plant Growth. W. E. TOTTINGHAM ......... 217 



A Study of Salt Proportions in a Nutrient Solution conaining Chloride, as 



Related to the Growth of Young Wheat Plants. 'S. F. TRELEASE ....... 222 



The Relation of the Concentration of the Nutrient Solution to the Growth of 



Young Wheat Plants in Water-Cultures. S. F. TRELEASE ......... ..... 225 



The Effect of Renewal of Culture Solutions on the Growth of Young Wheat 



Plants in Water-Cultures. S. F. TRELEASE and E. E. FREE ........... 227 



