1919] WATERMAN— ROOT SYSTEMS 23 



Standard measuring stick. When missing from any figure, the 

 scale is the same as that of the adjoining figure. 



On account of the range of the subject and the relatively small 

 amount of work done in it, the study has been largely a survey of 

 the ground, and the results must be regarded as indications for 

 future work rather than as final solutions of the problems. 



The work was carried on under the direction of Dr. H. C. 

 CowLES and Dr. Wm. Crocker, and grateful acknowledgment is 

 made to them for their advice and general assistance; as well as 

 to Dr. G. D. Fuller, Dr. Sophla. H. Eckerson, and Messrs. H. C. 

 Sampson, E. J. Kraus, and J. T. Buchholz. 



Synecology of Crystal Lake bar region 



geography and geology 



The region studied is located in the northwest corner of Benzie 

 County, Michigan, and comprises a strip of land about i mile wide 

 and 5 miles long between the west end of Crystal Lake and Lake 

 Michigan. Geologically it is probably a harbor bar formed during 

 Algonquin time between the ends of two glacial ridges extending 

 from Lake Michigan southeastwardly on either side of Crystal Lake. 

 There are some indications that this strip may have a morainic core, 

 but if so it was worked over and its top leveled off during the Algon- 

 quin high water, so that from an ecological standpoint the situation 

 would be the same. 



Soon after the recession of the post-glacial lake waters, the winds 

 began the work of piling up dunes. Apparently they were begun 

 much farther west on land since eroded away by the lake. The 

 group which may be called the Point Betsie complex starts in a 

 point on Lake Michigan at the western end of the grounds of the 

 Congregational Summer Assembly and spreads like a fan to the 

 north, about 2 miles in length and half a mile in width at its widest 

 part. At its southern extremity the dunes are fixed with a very 

 uneven contour, showing dune ridges and outlines of former blow- 

 outs, and covered by a climax forest. Approaching Point Betsie 

 the surface is lower and the fixed dunes give place to a complex of 

 moving sand containing residual patches of the original forest. 

 Above Point Betsie the dunes are fixed again and end with a definite 



