Robert Sturgeon wrote:
On Mon, 19 Sep 2005 21:37:00 -0500, "Martin H. Eastburn"
wrote:

(snips)


I doubt

there is much limestone as the large fresh water flow of the river
discourages marine corals. OTOH, low to moderate hardness sandstone should
start at the 80 to 100' depth and below about 10,000' it would turn into
metamorphic rocks like phylite and various schist.

Sandstone is metamorphic


No, it is not. It is sedimentary. Under enough pressure,
it in turn usually turns into quartzite, which is
metamorphic. For a good rundown on the various rocks, see
http://www.rockhounds.com/rockshop/rockkey/index.html

And no, I am not a geologist, just an interested amateur.

(rest snipped)

--
Robert Sturgeon
Summum ius summa inuria.
http://www.vistech.net/users/rsturge/

Yea, there seems to be a lot of "self styled" geologists around here.
Wonder how many of them ever took a geology course. :-)
...lew...