Class is out.

Okay! Okay! I know I goofed up my last report. I fell asleep leaning on the "paste" button. If the ditchweezil weren't such a strict school master we'd all have a delete function available to us. But he tries to hold us to a higher standard. I would imagine that my GPA is down the toilet by now. But after 20 years on submarines, I've gotten used to having my head in a lot of toilets while on liberty. I learned my lesson. Now it's your turn. Three years ago I got a visit from an old acquaintance from Florida. His live-in girlfriend had dumped him. Falling into depression, he soon lost his job. The problem was, his girlfriend wouldn't move out. So he decided to visit me until she had a place to move to. After a week of bleeding heart stories, and tears, I decided that a trip to the creek would shut him up. If it didn't? I figured I was in a perfect place to drown him with only a few snakes as witnesses. As it turned out I found the tips of four teeth sticking out of the creek bottom in the Ashley formation. From the tooth spacing I figured there could be a skull up to 24 inches lying upside down. The problem was that there was 6 inches of water. If you ask a hundred fossil collectors if they have ever put a plaster jacket on something, 95 will probably say no. Ask how many have put a jacket on a fossil in water and most likely that number will be 100. It's a unique problem that most collectors will never come across. Usually, when a fossil is found in the water, the excavation turns into a "salvage what you can" story. Add a little water current, or waves, and it can easily turn into a horror story. A good example comes to mind that concerns a local collector. He had found a very nice, articulated, Oligocene whale in a local creek. It was in a tidal zone where the water would vary between six and eighteen inches within just a few hours. Realizing that he had a complete skull he began to uncover it. He dug a trench around it and as he worked farther out he uncovered the right mandible, then some vertebrates, and finally a line of ribs. He continued to clean the matrix from around the items with one objective in mind. He wanted to take a picture of the whole thing in place. Picture taken! Mission accomplished. Now to remove the whale. What's this? The water is rising? Must hurry! CRUNCH! With so much material removed the skull had fallen apart. When I heard about his misadventure I went to the spot four weeks later and found numerous pieces of the skull. Some as far as 20 feet down stream. I returned them to the collector, who still hadn't figured out how to put it back together. I wish him luck! The lesson here, class, is to never try to excavate a large fossil in water. Unless you remove the water first. Building a three foot square dam, in even six inches of water, is not that easy. A building material must be used that will keep out the water long enough for a jacket to dry. On this particular trip this is what I did. Since the skull could be as long as 24 inches I dug a trench around it three feet by 18 inches. I dug the trench 8 inches deep and 12 inches away from the side. I did this without a dam around it so that the current would help wash the area out. That way I could tell if additional bones here encountered during the matrix removal. After we had the trench cleaned out sand was built up around the trench until it reached 6 inches above the water. I then placed large plastic trash bags on the outside of the dam. An additional six inches of sand was then placed on the garbage bags. Then we went to work bailing out the water. After the water was removed it was easy to keep up with the seepage with a small cup. I then had to decide what to wrap it with. I had a good supply of 6 inch plaster bandages on hand. The problem was that the block I planned on removing was soaking wet. I could have put a plastic bag over it first. That would keep the moisture from preventing the plaster wraps from drying. Or I could use foam. While in my early days of casting I had experimented with several methods of foam. These are the type that came in cans, for industrial use, and some with two part mixtures. Both have their advantages. I have used "Great Stuff" with good success out west where water was in short supply. It dries within an hour of application and will easily support items up to a hundred pounds. I've also used a two part mixture that hardens in an hour. I carry two 20 ounce Mountain Dew plastic bottles (Yes, I'm addicted too) filled almost half way. Each has one of the ingredients. Pour one into the other, shake vigorously, and then pour over the item after wrapping it in newspaper. The Great Stuff will only expand 3X. The two part mixture (Foamit-3 from Smooth on) expands 18X. You do the math! Both are 20 ounces in weight. Cost about the same. Do I see any hands yet? I decided to use the two part foam for this project. I wrapped the block with a dry garbage bag and used tape to hold it in place. I then used plastic screen (Patio screening) to put a six inch wide piece around the bottom. You can also use metal screen. But it's not as easy to carry around in the field inside a back pack. It's also easier to cut the plastic screen when you remove the jacket. I mixed up my concoction and slowly poured it over the entire block. But not two slowly! It sets up in 8 minutes. I mixed another batch and made sure that there was good coverage. The part that poured into the trench was unaffected by the small amount of water and expanded into the screen. A small vigilance for an hour, to keep the seepage out, and it was time to "Pop" the block out. This consists of hitting beneath the block with a shovel or large crowbar. The block will break loose cleanly at the jacket level if done right. If not... That's another lesson learned! But everything went fine and we carted the block back to my truck with the help of my home made stretcher. Listen up! There will be a test tomorrow. Bring your boots!