The objective of this research is to determine how the detrital component of the Wabash Formation varies in the vicinity of the Mississinewa-Liston Creek contact. As early as 1927, in the work of Cumings and Shrock (1927), it was noted that there was a decrease in the silica content of the Mississinewa Member in a traverse from Yorktown to Kokomo (30.28 percent at Yorktown to 15.90 at Kokomo).