Sent: Saturday, July 17, 2004 9:24 AM
Subject: RE: book club meeting: Thu 6/17

Present: Jim and Peter.  We discussed "Ancient Life of the
Great Lakes Basin" by J. Alan Holman. We were puzzled by his
description of the Michigan Basin:

	At the end of the Pennsylvanian period, ... there was
	an upwarping of the Great Lakes region that resulted in
	an erosional interval for the next 250 million years.
	As the gently downward-curving layers of sedimentary
	rocks in the Michigan Basin were slowly pushed upward,
	they were eroded away to form a pattern in which the
	youngest Paleozoic rocks were closest to the surface
	at the center of the basin, with successively older
	closest to the surface away from the center of the basin.

As far as we could tell, eroding the center of the rising
dome would wear away the youngest rocks in the center, so
the center should have the oldest rocks? If anyone has a
better explanation, please contribute!

Our next meeting will be Thu 9/2, 7pm, the book will be 
"The Future of Life" by Edward O. Wilson.

Peter
http://www.wideopenwest.com/~peterwchen/book.html