INTHODIcnoN-. 9 



rissuiit, the Florissant or I^.vcu.strim: kaina. Which of them is the older can 

 not be (let»'riuiii(<l until their faiiiias have been more completely stndied; 

 and even then, tor lack of siitlicient comparisons elsewhere on the conti- 

 nent, it may be impossiljle from the insect remains alone to reach any pos- 

 itive conclusions. When the structure of the Green river beds has l>een 

 more completely studied, their age can doubtless be determined with much 

 accurac); and a similar result may be reached when the age of the oro- 

 graphic movement shall have been determined which brought about the 

 emptj'ing and desiccation of the ancient Florissant lake. With these time 

 elements given, the extent of the insect remains in the Gosiute and Lacus- 

 trine faunas is such that the relations of deposits hereafter discovered may 

 quickly be made clear. 



The difference between the Gosiute and Lacustrine faunas is shown 

 to be much more remarkable when we examine the larger groups. Thus, 

 of the 66 genera found at Florissant, only 18 occin- also in the Gosiute 

 fauna, which contains, besides, 81 genera not found at Florissant, and there 

 are even a number of tribes which, as far as we yet know, are entirely 

 confined to one or the other fauna. 



Besides the beetles described or enumerated in this work, no fossil 

 Rhynchophora have been described from any formation. Tertiary or pre- 

 Tertiary, on the American Continent, with the single exce})tion of a species 

 of CurcuHonidtv which I have caWiid Ilyl oh iites cretacens^ and which was dis- 

 covered in the Pierre shales of the Assiniboine river, northwestern Manitoba, 

 by Mr. J. B. Tyrrell, of the Canadian Geological Survey, in 1888. 



In conclusion, the following statejnents inav be made regarding the 

 Rhynchophorous fauna of the American Tertiaries in general : 



(1) The general lacies of the fauna is American, and somewhat more 

 southern than its geograjjhical position wovdd indicate. 



(2) All the species are extinct, and though the Gosiute lake and the 

 ancient lacustrine basin of Florissant were but little removed from each 

 other, and the deposits of both are j)resumably of Uligocene age, not a single 

 instance is known of the occuirence of the same .species in the two basins. 



(3) No species are identical with anv European Tertiary fonns. 



'Cont. Can. raliimt., ii. :fll-:{l, jil. Ii. lig. ;'.. 



