IV PREFACE. 



with the subject, especially in the stages of the desiccation of the lake yet to come. Professor 

 M. A. Brannon, of the University of North Dakota, has carried out a series of cultures by 

 which the specific action of the micro-organisms upon the sulphates, iron, and calcium com- 

 pounds has been determined and some important facts bearing upon the changes in woody 

 tissue probably initial to the formation of coal have been obtained. Professor J. C. Jones, of 

 the University of Nevada, has made brief studies of the travertine coatings found on the 

 solid granite near the level of the highest beach line, establishing the participation of 

 biological agencies in their formation. Mr. S. B. Parish, of San Bernardino, has written 

 a description of the plants which form the vegetative setting of the drama of the appear- 

 ance and disappearance of the lake; the senior contributor has devoted attention chiefly 

 to the revegetation of the areas laid bare by the desiccation of the lake. The field parties 

 have been accompanied by scientific visitors at various times, from whom valuable sug- 

 gestions as to interpretation have been received. 



