GEOLOGICAL AND NATURAL HISTORY SURVEY. 53 



4. On west side of Des Plaines River, one-fourth mile north 

 of Santa Fe Railway bridge. An area of several square rods of 

 limestone surface is heavily glaciated. Grooves one-half inch in 

 width are common and there are a few fully two inches in width. 

 Fine lines are numerous. The bearing corrected for magnetic 

 variation is very nearly due west, the magnetic bearing being 3 to 

 4 degrees south of west. This striated surface slopes perceptibly 

 toward the southeast, there being a descent of 2 to 3 feet in as 

 many rods. The glaciation was therefore made on an ascending 

 surface. 



5. Immediately west of Summit on the west side of the Des 

 Plaines. The striae here observed are faint lines bearing S. 38 

 degrees W. 



6. Between Willow Springs and Sag bridge, in the bed of the 

 Drainage Canal. The striae here observed consist of faint lines 

 bearing S. 23 degrees W. They appear over a space of several 

 square yards. (See Fig. 6.) 



7. At Lemont, about 500 feet from the Santa Fe Railway 

 bridge. Mr. Ossian Guthrie reports that heavy grooves have a 

 bearing about S. 60 degrees W. They were exposed in the exca- 

 vation for the diversion channel for the Des Plaines. A view of 

 these grooves is given in Fig. 7, but the present writer thinks they 

 may be the product of the waters of the Chicago outlet rather than 

 glacial striae. 



8. Lyons, quarry in south part of village. Nearly all the 

 striae bear S. 70 degrees to 75 degrees W., but scattering striae 

 range from S. 44 degrees to S. 71 degrees 30 minutes W. 



9. La Grange quarry. Scattering striae on a planed surface. 

 Bearing S. 58 degrees 30 minutes W. 



10. Hawthorne quarry. There are here two sets, each quite 

 heavy scorings. The earlier set follow approximately the line of 

 strike of the dipping layers, bearing S. 64 degrees to 68 degrees W. 

 The later set cross the upturned edges of the layers at a small 

 angle, bearing S. 52 degrees to 54 degrees W. 



11. Quarry at crossing of Chicago avenue and Western ave- 

 nue, Chicago. A few faint striae preserved have a bearing S. 72 

 degrees W^. 



12. Excavation for Fullerton avenue conduit in north part of 

 Chicago. Bearing S. 60 degrees W. (recorded in profile of con- 

 duit). 



