4-02 



The National Geographic Magazine 



ba}- is nearly level, so that soundings 

 giving the depth of the water do not 

 disclose any valleys. By testing the 

 bottom at numerous points along lines 

 transverse to the general course of the 

 stream, it was found that off the mouth 

 of each stream was soft mud containing 

 organic matter and readily distinguished 

 from the glacial drift on either side. It 

 had been thought that the glacial clay 

 might be softened by being covered b}~ 

 water so long, but experience showed 



Figure i shows a cross-section of the 

 valley of Mills Creek, three-eighths of 

 a mile out from the present mouth. 



Figure 2 shows the depth in feet to 

 clay in the part of Sandusky Bay ex- 

 tending north from the mouth of Mills 

 Creek a distance of 2 miles. To avoid 

 crowding, some of the numbers have 

 been omitted. Along line A were made 

 41 holes 8 rods apart. Excepting near 

 the western end, the}* show the clay to 

 be everywhere 6 to 8 feet below the sur- 



One Mile 



Figure 4. — Valley Extending Under Marsh from Guston Inlet to Cedar Point 



that as a rule the weight of two men 

 would push the auger but a few inches 

 or a foot or two into this clay, whereas 

 it might be pushed 20 feet or more 

 into the deposits made since the glacier. 

 The agitation of the water by waves has 

 caused the loose mud to fill the original 

 valleys, making the bottom of the bay 

 approximately level. These valleys, 

 made by the streams when they flowed 

 miles farther than now to reach the 

 lake, are thus traceable by the lines of 

 soft mud. 



face — such uniformity as to indicate 

 that the original inequalities were planed 

 off by wave action. Line B, parallel to 

 A and almost 2 miles long, shows nearly 

 as much uniformity. From the place of 

 deep mud on line A a line of deep mud 

 extends to the present mouth of Mills 

 Creek and in the opposite direction to 

 the line of deep mud that marks the 

 former course of the Sandusky River. 



The valleys of two streams east of the 

 city, Pipe Creek and Guston Inlet, one 

 in the open bay and one in the marsh 



