255 BOTANICAL GAZETTE. 



lands and drift formations were probably high and dry long before the 

 immense lakes formed from the melting and turbid waters ceasedto be. 

 It was tolerably well understood that many species of trees and 

 other i)hnts which required a temperate atmosphere, retreated south- 

 wardly with the advance of the glacier, and advanced to higher lati- 

 tudes on the glacier's retreat.. Thus these higher ridges would be- 

 come timbered long before the lower lands became dry. Evidence 

 accumulates that man existed on this continent, in the far west, not 

 long after the glacier retreated, though "not long," in a geological 

 sense may mean many hundreds of j ears. The lakes of glacial water 

 would gradually become shallower from the deposit of the highly 

 comminuted material brought down from higher land, from the wear- 

 ing awayof rocky breastworks as in South Pass, 111., as well as from 

 the openings which would continually occur from nature's ever vary- 

 ing plan of streams under ground. In all events, the drying of these 

 lakes would be from their outward edges first. Aquatics would give 

 way to marsh grasses, and these to vegetation such as we now find 

 generally spread over the prairie region. If now we can conceive of 

 human being.s such as we know the Indian races to be, already in 

 more southern latitudes— having learned the fact that firing would keep 

 down trees and aid in the preservation of the chase — following the 

 retreat of the glacier to the higher lands, and still as they advanced 

 northwardly, firing the plains up to the water's edge, it would certain- 

 ly account for the absence of arboreal vegetation from these im- 

 mense lacustrine lands from the very beginning of their formation. Of 

 course with thisview we should have to look for some evidences of 

 man's existence, both on the lands which were once under water, as 

 well as those whichwere timber lands at his first appearance there. 

 He did not know how many such evidences have been 

 or may • be found. Man's traces in the past ' are at 

 best but rare, and they would naturally be much more scarce 

 in the lacustrine regions than in lands dry at the same epoch. At any 

 rate, this part of his remarks he said, must be taken as mere specula- 

 tion ; but as we cou'd see on the basis of sound scientific investiga- 

 tion why there could be no trees on these grassy prairies within the 

 range of indubitable history, it was a fair inference that some such 

 cause had continued from the beginning; namely, that annual fires 

 had ever been the reason why arborescent vegetation had never had 

 an existence there.— -/'/w. /V///. Acad. 



Oatalo,o:nc of Midiioran Plants.— This catalogue of 105 



pages IS the work of Chas. F. Wheeler and Erwin F. Smith of Hub- 

 bardston, Mich. There could not well be a finer state, botanically, 

 than Michigan. Cut up as it is into two peninsulas, with its diversified 

 conditions, it seems rich in rare plants. The catalogue is confined to 

 Phanerogams and Va.scular Cryptogams, and numbers 1,634 species. 

 It contains a colored map of the state and a preface describing the 

 general botanical features. The price is fifty cents and the authors 

 well deserve some acknowledgement of their laborious work. 



