204 G. L. COLLIE — WISCONSIN SHORE OP LAKE SUrERIOK 



been times when the waters advanced on the land instead of receding 

 from it; but these were teraporar}'- stages. The total result, however, has 

 been a gradual recession of tlie lake level to its present i)osition. The last 

 well defined stage, before the present one, may be called the Madeline 

 stage, from the fact that the benches made by it are well defined on 

 Madeline island. At that time the lake stood at least 10 feet higher 

 than at present. The terrace made during this stage is characterized 

 by its distinctness. A few sea-cliffs, also of this period, are found at 

 some distance from the present shore of the lake, and they, too, retain 

 their original features in a marked degree. In all probability the ter- 

 race and cliff are of recent origin. 



Closely associated with the sea-cliff and the bench at its foot there are 

 spit formations, in two instances at least. The spits were formed evi- 

 dently during the retreat of the lake from the Madeline stage to a lower 

 stage. As the lake level was lowered the spits were built out, until the 

 Grant Point spit at the south end of Madeline island exceeded a length 

 of one mile. This length was obtained during the time of maximum 

 withdrawal of the lake. 



Succeeding this maximum withdrawal there has now appeared a re- 

 advance of the lake on the land. This apparent rise of the lake is shown 

 by two proofs: (a) The destruction of shore deposits, especially spits 

 and bars, and (6) the drowning of the lower courses of streams which 

 empty into the lake. Under the first head ma}^ be mentioned the de- 

 struction of spits such as -that on the south end of Madeline island, or 

 of bars such as the Chequamegon Point bar. The former may be taken 

 as a type of the waning shore deposits. According to well authenticated 

 tradition, this spit once extended for a distance of 5,000 feet from the 

 south shore of the island. Nothing is now left but a shoal to mark its 

 former extent. This shoal shows that the extent of the spit has not been 

 exaggerated. It extends into the ship channel for a distance of at least 

 one mile. The shoal is a destructional form, not a constructional one; 

 it could not be formed under present conditions as a constructional 

 shoal; it is simply the foundation — a remaining remnant — of the Grant 

 Point spit. It is the testimony of a number of old residents on INIadeline 

 island that the spit extended out into the channel at least 2,000 feet 

 within 50 3^ears. The destruction of the spit has been a comparatively 

 rapid one, therefore. What is here stated with regard to this particular 

 formation is also true of others, but exact statements are wanting. The 

 only reasonable explanation of this rapid destruction of si)its is that 

 already indicated, namely, the advance of the lake on the shore, due 

 apparently to rise of lake level. In this connection it may be of value 

 to refer to Gilbert's ''^ " Recent earth movements in the Great Lakes re- 



