Miley was kind enough to send me a picture of a piece of Algae-on-a-Stick that I sent to her earlier. She has a photographic setup that I just can't match. She was able to capture the detailed "stick" in the middle that makes this fossil more of an accurate replacement than any I have ever seen before. You can read my main essay about A-o-a-S at the KinesavaTALKS blog page. It's a main menu item at the top.
I call it A-o-a-S because I have no idea what else to call it. My dad thought he was just collecting some nice agate that will take a great polish -- which it is. But after I made some microscope slides from one of the rocks in college, I knew they were more than that. ALL of my A-o-a-S has some kind of stick in the middle but they're seldom the same kind. The one in this photo appears to be a hollow reed. If this was ordinary petrified wood, that would be a cast in the middle. It's not. You can see the individual plant vesicles around the outside wall.
I have to confess to some frustration with these rocks. After a lifetime of experience with my dad's rocks and more rock shows and rocks than I can count, I can't understand why people aren't more excited about them. Miley's photo shows the structure of the original plant that could be straight out of a botany textbook. This thing is millions of years old. Fossil replacements are just never this clear and perfect -- except these.
I think there is a story about these that is similar to the way the famous Burgess Shale fossils were preserved. If you're a paleontologist, send me a message.