496 BOTANICAL GAZETTE [JUNE 
that there are 3 main levels bordering the stream: (1) Low 
terraces, into which the present stream is now cutting. During 
high waters a portion of this may be inundated. Gravel is overlaid 
with a deposit of peat, ranging in depth from an inch or so to 3 or 
4 ft. This level is covered with a willow thicket association in 
which the dominant forms are Salix chlorophylla Anders. and 
Fic. 3.—View of Boulder Park looking west: James Peak at left and Continental 
Divide in background; glimpses of stream may be seen flowing through willow thicket 
association; note lighter colored patches of dry grassland; slopes are clothed with 
aspen, lodgepole pine, and Engelmann spruce-subalpine fir. 
S. padophylla Rydb. (2) Middle terraces, meander terraces much 
older than the preceding. On the middle level the gravel is not 
overlaid with peat, except in a few places. The soil is a sandy and 
gravelly loam and 4-8 inches deep. The characteristic vegetation 
is meadow scrub in which Salix glaucops Anders., Betula glandulosa 
Sarg., Dasiophora fruticosa (L.) Rydb., and mesophytic herbs are 
dominant. (3) High terraces, which are composed of glacial gravels 
which have been worked over by the stream which issued from the 
