Among articles to appear in early 
numbers of the Journal of Geology 
are the following: 
- The Physical Chemistry of the Crystallization and Magmatic Differ- 
entiation of Igneous Rocks. Parts II, II, and IV. By 
J. HL. Vor. 
Types of Rocky Mountain Structure in Southeastern Idaho. By 
GEORGE ROGERS MANSFIELD. 
Cycles of Erosion in the Piedmont Province of Pennsylvania. By 
F. BAscom. 
Discussion of ‘‘Summaries of Pre-Cambrian Literature of North 
America,” by Edward Steidtmann. By T. T. QUIRKE. 
The Nature of a Species in Paleontology, and a New Kind of Type 
* Specimen. By Epwarp L. TRoxELL. 
| The Pleistocene Succession near Alton, Illinois, and the Age of the 
Mammalian Fossil Fauna. By Morris M. LEIGHTON. 
Theoretical Considerations on the Genesis of Ore-Deposits. By 
Palo RASTALL, | 3 
Note on a Possible Factor in Changes of Geelauteat Climate. By 
HARLOW SHAPLEY. 
The Horizontal Movement of Geanticlines and the Fractures near 
Their Surface. By H. A. BROUWER. 
Diastrophism and the Formative Processes. XIV. Groundwork 
for the Study of Megadiastrophism. By T. C. CHAMBERLIN 
and R. T. CHAMBERLIN. 
