i 9 o 9 ] 



BURNS— BOTANICAL SURVEY OF HURON VALLEY 



45 1 



I 





entering the bog from the north one passes through a number of large 

 areas of bog shrubs, wholly or partly surrounded by tamaracks. In 

 these areas are sometimes found small patches of tamarack and spruce. 

 A profile was run across the bog, north and south, through these areas 

 and the open water. This shows that the areas occupied by tama- 

 racks are located over shallow places in the post-glacial lake, and 

 that areas of bog shrubs are located over deeper basins. The borings 

 showed that this lake had a number of basins very much the same as 

 found at Dead Lake. It has reached a later stage of development, 

 however; the dominant vegetation is the bog shrub and tamarack. 



Fig. 5 .-Profile north and south through Snow's Lake. The dotted line shows 

 the water level before drained. Scale: vertical 1:300; horizontal, 1:3048. 



Snow's Lake/— This lake is located about fifteen miles (24 km ) 

 west of Ann Arbor. It was formerly a very large lake, but has been 

 almost filled with peat and marl. The bottom of the post-glacial 



(fig 



This profile 



runs north and south. The deepest and largest basin was near the 

 northern shore; the southern part of the lake was comparatively 

 shallow. A few years ago the lake was drained at the northeastern 

 corner and the level of the water was lowered in the lake. Over the 

 shallow parts of the lake the peat had already become solid, and the 

 draining did not change the level of the surface. Near the open 

 water, however, the plants were still floating, and when the water was 

 drained they sank to the new level. The surface today slants rapidly 

 toward the water; especially is this true for the first few rods immedi- 

 ately next to the open water. It is very surprising from the road to 

 see fine large oak trees growing apparently in the peat bog. How- 



4 A careful study of this lake was made by D, Jeax Dawson, but the results have 

 not been published. 



