- GeoRef, Copyright 2008, American Geological Institute. Reference includes data from Bibliography and Index of North American Geology, U. S. Geological Survey, Reston, VA, United States
Orthoceracone cephalopods and crinoid orientations were studied in middle Silurian Waukeshaw beds in a quarry 1/2 mi. N. of Lemont, Illinois, and between the Sanitary and Ship Canal and the Des Plaines River. Orientation readings on 106 specimens were made to determine in which direction they were lying. Two trends were found, the major, WNW., and the minor, SSW. Crinoid stems were mainly oriented in the same directions. These directions indicate a wind and current from the WNW. Such orientation studies show that it is possible to examine certain ecological measures over essentially "instants" in time.