Thanks maeve. Took awhile to figure out what cache means, and where to find it, but once I did, was pretty simple to do.

Sharing the following for any other ignorant folks like me who might want to try to retrieve a thread or posts lost in the crash.

When I googled the thread, I got a number of links. One example -
Mudcat Café message #3700583
www.mudcat.org/detail_pf.cfm?messages__Message...
The Mudcat Cafe
Feb 5, 2015 - The Mudcat Café TM Thread #156504 Message #3700583 ... Thread Name: BS: Birdwatching 2015. Subject: RE: BS: Birdwatching 2015.

When I opened the links, all that was there was "Mudcat Cafe TM" Eventually I saw, when I went back to the google page with the list of links, that there was a small arrow indicating a drop down menu after "cfm?messages__Message". When I clicked that arrow, the word cache appeared in a box, and when I clicked the box, the content of the message appeared.

fwiw, I found it easiest to copy and past each message into a wordprocessing document which I could then manually sort by date and time, and copied and pasted from the wordprocessing document to try to insure the copied messages would be in date order here. The list of links on google was not in chronological order.

I'm sure more tech savy folks could have done this more easily, but I also know I am not the only tech-challenged person on Mudcat, so hope sharing my experience is useful to some.