<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML><HEAD> <META http-equiv=Content-Type content="text/html; charset=iso-8859-1"> <META content="MSHTML 6.00.6000.16608" name=GENERATOR> <STYLE></STYLE> </HEAD> <BODY id=role_body style="FONT-SIZE: 10pt; COLOR: #000000; FONT-FAMILY: Arial" bottomMargin=7 bgColor=#ffffff leftMargin=7 topMargin=7 rightMargin=7> <DIV><FONT face=Garamond color=#008000 size=3>Thanks so much to all who answered me.  The Marler paper I was referring to was the Geological Survey Paper 435.</FONT></DIV> <DIV><FONT face=Garamond color=#008000 size=3></FONT> </DIV> <DIV><FONT face=Garamond color=#008000 size=3>Lots of information to follow up on.  I appreciate it.</FONT></DIV> <DIV><FONT face=Garamond color=#008000 size=3></FONT> </DIV> <DIV><FONT face=Garamond color=#008000 size=3>Meg</FONT></DIV></BODY></HTML>