CONTENTS OF VOLUME XIX 
Foreword. By President Clark W. Chamberlain 1 
1. Echinodermata of the Brassfield (Silurian) formation of Ohio. By 
Aug. F. Foerste 3 
2. America’s Advance in Potash Production. By W. C. Ebaugh 33 
3. The Use of Outline Charts in Teaching Vertebrate Paleontology. By 
Maurice G. Mehl 47 
4. Some Factors in the Geographic Distribution of Petroleum. By Maurice 
G. Mehl 55 
5 . Notes on Isotelus, Acrolichas, Calymene, and Encrinurus. By Aug. F. 
Foerste 65 
6. Some Suggested Experiments for the Graphic Recording of Speech Vibra- 
tions. By Robert James Kellogg 83 
7. The Manipulation of the Telescopic Alidade in Geologic Mapping. By 
Kirtley F. Mather 97 
8. The Importance of Drainage Area in Estimating the Possibilities . of 
Petroleum Production from an Anticlinal Structure. By Kirtley F. 
Mather and Maurice G. Mehl 143 
9. Psychological Factors in Vocational Guidance. By Thomas A. Lewis 147 
10. The Use of Models in the Interpretation of Data for Determining the 
Structure of Bedded Rocks. By Maurice G. Mehl 157 
11. Some Suggestions for Indicating Drilling Operations. By Maurice G. 
Mehl 169 
12. The Kimmswick and Plattin Limestones of Northeastern Missouri. By 
Aug. F. Foerste 175 
13. Education for Scholarship. By William E. Castle 225 
14. The Cytology of the Sea-side Earwig, Anisolabis maritima Bon. Part 1. 
By Sidney I. Kornhauser 234 
15. Notes on Arctic Ordovician and Silurian Cephalopods. By Aug. F. 
Foerste 247 
16. Revolution vs. Evolution: The Paleontologist Renders His Verdict. By 
Kirtley F. Mather 307 
Subject and Author Index 325 
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