314 



FRANCIS RAMALEY 



N/> E TEM 



Fig. 1. Map of Clear Creek valley and canyon just north of Georgetown, 

 Colorado. Enlarged, with revisions from the topographic map of the George- 

 town quadrangle, U. S. Geological Survey; contour interval 500 feet; buildings 

 indicated by black rectangles. The area of the present study is chiefly close to 

 and just west of the automobile highway. The ponds shown on the map are arti- 

 ficial and subject to frequent changes in outline. Arabic figures on the map have 

 the following significance: 1 = standing water; 2 = sand without vegetation, fre- 

 quently overflowed; 3 = loose sand with shrubs; 4 -- sand and rocks with various 

 shrubs and herbs such as are present in inceptive mixed grassland; 5 = same as 

 preceding but with a number of trees; 6 — loose sand with wheat grass; 7 = early 

 stage of Bouteloua association but with many shrubs of Chrysothamnus; 8 = 

 Bouteloua and other short grasses; 9 = inceptive mixed grassland; 10 = derivitive 

 mixed grassland; 11 = streambank fringe forest of alders, willows and cotton- 

 woods. 



