INTRODUCTION, 



rpTHE voknne herewith offered to the public is the first, in the order of pub- 

 -*- licatiou, of the zoological series of the reports of the State Geological 

 Survey of California. This survey, although called simply " geological," was 

 intended to embrace within its scope the natural history and topography of the 

 State as well as its geology. The Act under which the work was organized 

 expressly requii'ed of the State Geologist " a full and scientific description of 

 the botanical and zoological productions of CaUforuia." Provision was also 

 made for the collection of specimens in all branches of natural history ; these 

 were to be arranged and labelled and held in charge by the Survey, until 

 suitably disposed of by the Legislature. By a later Act the collections of 

 the Survey were ordered to be turned over to the State University, wluch 

 will be dune whenever a building has been prepared for their reception. 



In carrying out the intentions of the Legislature with reference to the zo- 

 ological department, an assistant was appointed, whose duty it should be to 

 visit different portions of the State and make collections of animals, studying 

 in the field their distriljutioa and liabits, thus providing the materials to 

 be worked up and prepared for publication by specialists in the different 

 branches. The gentleman selected for this position was Dr. J. G. Cooper, 

 who had been employed in the same capacity on the United States Pacific 

 Piailroad surveys, and who was already well and favorably known to the 

 scientific world by various publications relating to the botany and zoology 

 of the Pacific States. 



Dr. Cooper was steadily employed in collecting, from December, 1860, to 

 April, 1862, and during a considerable portion of the year 1863, being assisted 

 for six months of 1862 by Dr. Edward Palmer. Tlie regions examined were 

 chiefly the Colorado Valley near Fort Mojave, the route to the coast from 

 that fort, the vicinitv of San Diego and San Pedro, and Santa Barbara and 



