X BIOGRAPHICAL SKETCH. 



The subject of the f'aunal relations of animals was a favorite one with 

 LeConte. He returned to it again and again ; he was the first to district 

 much of the vast and then almost unexplored regions west of our prairie 

 country. The foundation of this work was laid in his essay on the dis- 

 tribution of California beetles, read to the American Association in 1851 ; 

 with slight modifications the conclusions then reached were confirmed in 

 the Stevens division of the Pacific Railroad survey, published in 1860 ; 

 while in the same year a more elaborate and extended survey of the whole 

 western country (excepting the then still unexplored region of the Great 

 Basin) was given in his Coleoptera of Kansas and New Mexico. In 

 this, following only in part the divisions suggested by Agassiz (who first 

 laid down the primal geographical boundaries of North American faunas), 

 he showed wlult remarkable difiierences were to be found within compara- 

 tively restricted areas in the western portion of our country, and laid 

 the foundation for the special work that has since followed, in which the 

 region here first mapped has been the point of greatest dispute. 



He carried these studies a stage further when in his presidential ad- 

 dress to the American Association in 1875, he attempted, by collating 

 the known fiicts concerning the actual distribution of certain of our 

 Coleoptera which afi'ect the sea-shore, but are also found in outlying spots 

 upon the beaches of inland lakes, to prove the comparative antiquity of 

 these forms; some of them, he endeavored to show, were unchanged 

 survivors of species which lived on the shores of the cretaceous ocean 

 when the Rocky Mountain and Appalachian districts were separated by 

 a wide stretch of open sea, and other species were either older or some- 

 what less ancient. By investigations of- this kind he hoped that we might 

 recover important fragments of the past history of the earth, where the 

 rocks disclosed no proofs. It must, however, be said that such proposi- 

 tions are to be considered speculative, until supported here and there by 

 the discovery of at least a few types from the tertiaries, if not from older 

 rocks, identical with those now living upon the surface. It is not much 

 to say that no such proofs have yet been found, for the careful study of 

 fossil Coleoptera has scarcely more than begun, and in our own country 

 of the numerous forms which have been exhumed at Florissant and other 

 localities, already amounting to four or five hundred species of Coleoptera, 

 very few indeed have been published. If, upon careful study, none out 

 of this considerable number should prove identici\l with living types, and 

 especially if species should occur nearly related to the forms specified by 

 LeConte in the way of illustration, the force of the considerations pre- 

 sented by him will be weakened, and some modified explanation will be 



