14 
The American Geolopist. juiy, 1901. 
5. The thin clay ])cirtino-s which occur in the seams of the 
hollows are inconsistent with uniform deep water conditions, 
l)ut are more easily exi)lained as heach phenomena. The mud- 
dy water often left in a trougli after the storm will drop its 
finer material, which was held in suspension, and so produce 
the clayey layer. 
6. The crests of the ridges are sometimes truncated, which 
suggests erosion of previous deposits, and implies shallow wa- 
ter. 
7. The surfaces of the ridges sometimes bear the common 
small ripples, one to three inches across. Figure 9, plate IV, 
shows such small ripples over the crest of the ridge shown in 
figures 7 and 8. (The arrows placed on figures 7 and 8 point 
out the location of the ripples.) Their size may be estimated 
from the foot-rule lying beside them. The lower seams of the 
ridge also bear suggestion of fine rippling. 
8. The ridges sometimes preserve the marks of the waves 
that softly glided up or over them. As described above, wave- 
lines showed clearly on the ridge photographed for figure 5, 
but are not brought out in the view. Wavelines are quite un- 
mistakable features and their presence would seem to make the 
conclusion unavoidable that the deposits which hold them are 
b)each deposits. 
THE MICHIPICOTEN HURONIAN AREA. 
A. B. WiLLMOTT, Sault Ste Marie, Ont. 
On the northeast shore of lake Superior is a tract of about 
•5.000 square miles knowij as the "Michipicoten Mining Divis- 
ion." Originally set apart because of the discovery of gold- 
liearing quartz, it now promises to become of more importance 
l3y reason of its iron beds. The tracing of the iron belt dur- 
ing the past summer has given some better idea of the geolog- 
ical structure than was previously known. 
The oldest rocks of- the district are the greenstorre schists. 
Some of these are undoubted lava flows, showing the charac- 
teristic elliptical structure described by Clements.* as occur- 
ing in the Crystal Falls "Hemlock formation. At a number of 
points agglomerates are found, as at Little Gros Cap fish sta- 
•Mon. xxxvi, U. S. Geo!. Sur. 112-124-. 
