56 Geology 



of a system of planetesimals. The computations are made from the Laplacian law 

 of density, and then the influences of certain secondary hypotheses are considered. 

 Professor Stieglitz makes a study of the conditions for precipitation and depo- 

 sition of calcium sulphate, calcium carbonate, and calcium bicarbonate in the 

 presence of atmospheric carbon dioxide. 



No. 87. The California Earthquake of April 18, 1906. Report of the State Earth- 

 quake Investigation Commission, ANDREW C. LAWSON, Chairman. 

 Quarto, two volumes and atlas. 



Vol. i (in 2 parts). Report of the Commission. Published 1908. 

 Part I, pages xvm+254, plates 1-98, text figures 1-54. 



Part II, pages 255-451, plates 99-146, text figures 55-69. " $17.00 



Atlas contains 25 maps, relating to volume i and 15 sheets of seismograms re- 

 lating to volume 2. J 

 Vol. 2. Mechanics of the Earthquake. By H. F. REID. 200 pages, 2 plates, 62 

 text figures. Published 1910. Price $2.00. 



This is the report of the State Earthquake Investigation Commission appointed 

 by the Governor of California to study the earthquake of April 18, 1906. The 

 fault where the earthquake originated is a part of a larger physiographic feature 

 known as the San Andreas rift. This rift and the geology of the coast system of 

 mountains are carefully described in the first volume, which is mainly descriptive. 

 Then follow detailed accounts of the displacements along all parts of the fault and 

 descriptions of the effect and intensity of the shock in all parts of California and 

 the neighboring States, where it was felt. All the phenomena observed are de- 

 scribed, including the visible undulations of the ground, the formation of cracks, 

 fissures, landslides, etc. The permanent displacements of the ground, as determined 

 by geodetic measurements, are given, and the positions of certain monuments 

 erected for the purpose of determining future slips on the fault are recorded. 



The second volume, on the mechanics of the earthquake, contains a theoretical 

 discussion of the phenomena described in the first volume. It traces the forces 

 required to cause the rupture at the fault to drags applied from below, and points 

 out that the rupture was necessarily preceded by a relative displacement of regions 

 on opposite sides of the fault, which suggests a method of anticipating certain 

 earthquakes. The records obtained by seismographs in all parts of the world are 

 given and discussed. A very complete mathematical theory of seismographs is given. 



No. 57. WASHINGTON, H. S. The Roman Comagmatic Region. Octavo, vi-J-199 

 pages, 3 text figures. Published 1906. Price $1.00. 



A petrological discussion of the main line of Italian volcanoes, from Lake 

 Bolsena to Vesuvius. Complete and detailed, largely quantitative, descriptions, 

 and numerous new chemical analyses of the various rock types are given, and their 

 mutual relations and the general petrological characters of the petrographic 

 province are discussed at length, the basis of the discussion being largely chemical. 

 The descriptions and treatment are in accordance with the Quantitative Classifica- 

 tion of Igneous Rocks, of the methods and terminology of which this work serve* 

 as an example, though the ordinary rock names are also used. 



No. 46 ADAMS, F. D., and E. J. COKER. An Investigation into the Elastic Constants 

 of Rocks, more especially with reference to Cubic Compressibility. Oc- 

 tavo, 69 pages, 16 plates, 26 figures. Published 1906. Price $1.75. 



In the report on this investigation the amount of cubic compressibility which 

 rocks undergo when submitted to pressure before they begin to flow, or under 

 conditions when they are unable to flow, is determined. In arriving at these results 

 the elastic constants of the rocks were investigated. Fifteen typical rocks, repre- 

 senting the chief types of acid and basic plutonic rocks forming the deeper portions 

 of the earth's crust, were studied, together with certain sedimentary and meta- 

 morphic rocks. A comparative study was also made of the cubic compressibility 

 and elastic constants of plate glass. 



