282 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1937 



into a single sheet of water as long as Lake Ontario but much wider. 

 Thus Lake Uinta came into being. 



Up from the north shore rose the great swelling bulk of the Uinta 

 Range, its flanks green with forest. This forest may or may not 

 have its counterpart living anywhere in the world of today; never- 

 theless, it must have been much like the forest that would develop on 

 the southern slope of a high mountain on the present Gulf coast of 

 the United States, could we but conjure up a mountain in that region. 

 Just as such a forest would have different kinds of plants growing at 

 successively higher levels, so it is probable that the forest which clad 

 the Uinta Range in that ancient epoch was also zoned according to 

 the altitude. Fossil leaves, flowers, seeds, and even pollen grains 

 collected from the bottom deposits of the ancient LakeUiuta enable 

 us to reconstruct the probable floral zones of a landscape that existed 

 during the Eocene epoch more than 30 million years ago. 



At the water's edge grew bur reeds, rushes, water milfoils, and the 

 familiar purple-spiked pickerel weed. But upon the shore and the 

 wide flats adjacent to it grew trees whose nearest relatives — japonica, 

 figs, and a variety of aromatic shrubs and trees — now live in the warm- 

 temperate parts of the earth. Vines, very similar to if not identical 

 with our modern grape, grew along with gourds, delicate climbing 

 ferns, and the less inviting cat briers. "\Miere the bottom lands were 

 sandj^, palm leaves cast their slatted shadows on the ground. 



If we could have gone back through the swampy bottoms we would 

 have found, among others, mimosa trees and trees related to the 

 cinnamon growing with a large variety of ferns and evergreen shrubs. 

 Pushing farther into the drier foothills, we would have passed through 

 woods of oak, maple, hickory, and gum — woods nearly indistinguish- 

 able from the present hardwood forests of temperate North America. 

 Higher up, pine and hemlock supplanted these familiar hardwood 

 species, and in the highest parts of the range forests of spruce and fir 

 predominated. That the evergreen forests were remote from the 

 ancient lake is attested by the fact that only one seed and the tip of 

 one twig of these species have ever been discovered in the lake deposits, 

 though leaves of lower-zone types are found there by the hundreds. 

 Nevertheless, forests of pine and spruce flourished; their former 

 presence is manifested by an abundance in the lake deposits of their 

 odd pollen grains, each of which is fitted with two bulging air sacks 

 that aided it to float many mUes from the parent tree. 



The insects, too, resembled rather closely those now living. Cad- 

 dice-flies, whose larvae buUd about their bodies little masonry houses 

 of sand grains or well-joined "log" houses of tiny twigs, frequented 

 the shallow water at the lake's margin, together with the more famil- 

 iar dragon fhes. The wobbly-legged crane fly was there with his 

 diminutive cousins, the midges. Beetles, crickets, and the homely 



