(no subject)
There are lots of different fossel types but a new one to me is burrows of extinct animals like a land based extinct type of beaver:
http://www.proctormuseum.us/Nebraska/Nebraska%20Fossils/Terrestrial%20Beaver%20Dens/Paleocastor.htm
http://www.nationalparksgallery.com/item/7739/type/pictures - check out all the pictures
http://www.travel-notes.org/gplains.html
http://www.fieldadventures.org/flinthill/burrow.html
http://www.paleoportal.org/fossil_gallery/detail.php?submission_id=1175
http://mek.oszk.hu/02700/02736/html/kepek/437.jpg
http://www.bentonsd.k12.pa.us/On%20Line%20Science%20Lessons/Evolution/grassmammals/demo.htm
The all seem to be twisting in the same direction (the opposite direction as the grooves on a normal screw or bolt). I wonder if that is because most of them are the same in terms of left or right handed or if insticts make them do it that way no matter which side is dominant.
***edit***
here are some that do go the same way as a screw (or the image was reversed)
http://mek.oszk.hu/02700/02736/html/kepek/436.jpg
http://www.nationalparksgallery.com/items/7750.jpg
