Stratigraphic Correlation

Stratigraphic or Geologic ColumnStratigraphic columns are drawn with the oldest strata at the bottom and the youngest at the top. Unlike stratigraphic sections, stratigraphic columns also indicate the age of the various strata on the column. Geologic age is shown as labeled bars to the left of the column that span the units of the appropriate time intervals. Because stratigraphic columns, like stratigraphic sections, are scaled to strata thickness, the lengths of the time period bars on a geologic column are not scaled to time duration.

http://www.gg.uwyo.edu/content/lectureActivities/geologic_time/correlation/strat_column2.asp?color=&title=Geologic_Time&subTitle=A_Correlation_Exercise&taskNum=3&callNumber=12193&Worksheet=&AnswerKey=

• http://igs.indiana.edu/FossilsAndTime/using.cfm 
• http://grandcanyonhistory.clas.asu.edu/history_science_geology.html