(58 PALAEONTOLOGY OF CALIFOKNIA. 



From the length of time that has elapsed since the publication 

 of these volumes, the author of the Tertiary Palaeontology, which 

 they contain, has in most cases forgotten his own species, and 

 has repeatedly declared his inability to assist me; the originals 

 of the descriptions are inaccessible, packed away with the great 

 bulk of the government collections in the cellars of the Smith- 

 sonian Institution, and I have been obliged to trust almost en- 

 tirely to my own acquaintance with the subject, in unravelling 

 the tangled skein of the synonymy of the West Coast Tertiaries. 



Under these circumstances, therefore, it will be surprising if I 

 have succeeded, in every instance, in correcting the names of the 

 species; and, doubtless, differences of opinion will always exist 

 in many cases. I have, however, endeavored conscientiously to 

 work out the problem before me, and, should my labors provoke 

 criticism, my only reply shall be — Go thou and do better. In 

 determination of the living forms, I must acknowledge particular 

 indebtedness to Dr. J. G. Cooper, of the Survey, and Dr. P. P. 

 Carpenter, of Montreal. The latter gentleman has gone over 

 nearly all of the recent mollusca collected by the Survey; and 

 West Coast conchologists depend to a great extent on his opin- 

 ions, based as they are on a most extensive acquaintance with 

 the subject. 



