NO. 3 DUNKLE I PLANT ECOLOGY, CHANNEL ISLANDS 249 



for long-period intervals between observations. This was necessitated 

 by the difficulties encountered in arranging for frequent trips to this 

 isolated island. Soil samples were taken at each of the instrument- 

 stations for mechanical analysis and hydrogen ion determination. 



While these investigations are necessarily incomplete because of 

 weather hazards, distance, and war-time restrictions, and some of the 

 conclusions hypothetical, it is hoped that the methods used and the 

 problems discussed may be of value to other students of insular condi- 

 tions and to the administrators of the various islands. 



The scope of this ecological study has involved the cooperation of 

 specialists in many fields. Meteorologists, oceanographers, geologists, 

 climatologists, and zoologists have contributed to the solution of the 

 ecological problems. Because of the diversity of the separate fields in- 

 volved in this study a glossary of technical terms is given. See p. 332. 

 The field of this investigation has covered such a large area, so difficult 

 of access, that it has made other assistance essential. Merely to name 

 all who have contributed in some measure to the success of the under- 

 taking would be impossible. However, this account would be incomplete 

 without mention of those whose assistance has been indispensable. 



First among these has been Dr. John A. Comstock, Curator of 

 science in the Los Angeles County Museum, whose leadership in the 

 organization of the expeditions of the Los Angeles County Museum 

 Biological Survey of the Channel Islands has made them possible. 

 Don C. Meadows, the field executive of the island expeditions, assisted 

 in the field work and in the organization of the material. 



The scientific interest of Captain Allan Hancock and his generosity 

 with the Velero III provided transportation for many of the voyages. 

 The use of the sedimentation laboratory of the Allan Hancock Founda- 

 tion facilitated the detailed study of the soils and marine sediments of 

 the island area. The patrol boats of the California Fish and Game 

 Commission also assisted in the matter of transportation. 



n Insular Environment 



The continental shelf of the western coast of North America is 

 very narrow when compared with that of the eastern coast. Off central 

 California the edge of the shelf roughly parallels the coast, trending 

 30 degrees east of south. At Point Conception the coast turns abruptly 

 eastward and then swings southward to regain its original trend only 

 along the coast of San Diego County. As the edge of the shelf does not 



