378 BOTANICAL GAZETTE [May 
coast, they reach their highest development northward, espe- 
cially at the summit of the terraces and bluffs. Perched dunes, 
it would seem, are favorably located for destruction by the wind. 
At Frankfort and Empire the perched dunes are in the earlier 
stages of rejuvenation. At Glen Haven these dunes have been 
rejuvenated, the vegetation entirely destroyed, and the sand 
and. 
Fic. 26.—Development of a juniper heath in a pasture at Beaver is] 
jously 
removed inland to form the gigantic moving dunes previe™ : 
mains 
mentioned. The substratum on which the dunes re 1] the 
as a bare gravel mesa, with only the Sleeping Bear lett _ t ely 
tale of its former occupation by coniferous dunes. It : ie 
possible that some of these so-called rejuvenated dunes i 
never been established, and that they have grown slowly si : ra 
present height pari passu with the vegetation. This 38 oer 
theory without any facts whatever to support it. _ d by 
seems to point unmistakably to an establishment follow’ ™ 
