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206 the gravel and sand of No. 2, or they may be mostly embedded in No. 3. The thickness of No. 2 is exceedingly variable. It is usually less than forty feet in level tracts, but it may be more than a hundred, depending on the duration of the cause that brought it there, and its operation at that point. It sometimes probably entirely replaces No. 3 and No. 4, and lies on the rock. The bowlders found within it are generally not scratched, but sometimes they are scratched, evidently by glacier-action. A great number of glaciated bowlders in this member of the drift have been seen at an excavation near the Falls of St. Anthony.

The following diagrams, Figs. 1 and 2, will express more fully the arrangement of the strata in this member of the drift, and give an idea of the manner of union with the succeeding member below. Fig. 1 is sketched from Nature, and shows a section of the laminated clay exposed in a railroad-cut near Toledo, Ohio:



Fig. 2 is also sketched from Nature, and represents the alternation of parts as seen in No. 2, and manner of junction with No. 3 at the Falls of St. Anthony. No. 2 here consists of the stratified gravel and sand which constitutes the surface of the drift (immediately below the soil) in large portions of the State of Michigan, Central and Southern Ohio, Northern Indiana, and Central Minnesota. It also forms the principal component of the well-known ridges in Northwestern Ohio, popularly but erroneously styled "lake-beaches." The materials are usually much water-worn, but, at the Falls of St. Anthony, many of the bowlders embraced in No. 2 are conspicuously glacier-marked, a circumstance which plainly indicates the agency which transported and deposited the whole mass in which they occur.