ECOLOGY. 411 



billed use of succession, climatology, and geology afforded the most 

 promising basis not only for interpreting deposits in terms of lowland 

 conditions, but also for sketching climatic and vegetative conditions 

 on the uplands. As a consequence it was proposed to treat sedi- 

 mentation as an essential feature of the organization of paleo-ecology 

 and to make the Bad Lands the particular seat of investigation. 

 Moreover, it was clearly recognized that the study of existing sedi- 

 mentation must go forward at the same time, and that the best oppor- 

 tunity for this lay in the successional studies of bad lands, dunes, and 

 playas already under way. 



During the current year general studies of deposition have been 

 made in various bad lands, in dunes in California and Oklahoma, and 

 in playas from California to New Mexico. The investigation of bad- 

 land strata and layers has been made chiefly in the Bridger of western 

 Wyoming and the John Day series of central Oregon. This had to do 

 chiefly with the thickness, order, grouping, and extent of the various 

 beds and layers, as well as the materials, cementing substances, etc. 

 An attempt was made to construct hypothetical topographies for 

 certain horizons, but in the absence of areal maps for the different 

 deposits these could be suggestive only. The general correlation of 

 the various layers with climate and vegetation proved more feasible 

 and afforded a number of promising leads for further study. 



