Floatation and Field Trips

Today my migraine is 95% gone, so I feel fine, but can't think straight or remember what I'm trying to do.
I got to do floatation today with another girl from our group. We were the last two to go. Our professor drove us to the University in Kirkwall where all of the soil samples go. The purpose of floatation is to determine what the soil samples consist of. The procedure is pretty simple, but time consuming if done carefully, which is very important so that there is no cross-contamination. We dumped each sample into a large, watery box, and then mixed the water and soil all around. The bits that float were collected by a small sieve that collects bits >1mm and the bits that float but are smaller than 1 mm, pass through that sieve and are collected by a second, smaller sieve that catches everything that is >300 microns.
When the sample was thoroughly stirred so that all the floating materials were out, and so that the plain dirt had a chance to wash out of the gause under the sample, we drained the water and examined the "residue", which is what's left. It usually consisted of gravel, some larger rocks, non-floating charcoal, burnt and 'cremated' bone, and occasionally chips of flint, or pieces of pottery that were missed during the initial excavation. We took out any small finds, (which were flint and pottery for us today), and then carefully described what and how much of each material was in the residue, the >1mm sieve, and the >300 microns sieve. The >1mm sieve usually had bits of plant mater, rootlets, and cramp in charcoal. The particles from the >300microns sieve are too small to describe with the naked eye, exceppt for the ratios of charcoal to grit.
There was a comment section on the information sheet where we needed to include any other relevant pieces of information, such as if the sample contained clay that was washed away. If so, we recorded what color the clay was, (usually yellow or grey for us today.) We needed to include the fact that a live spider was removed from the >1mm sieve once, because pollen or residue of the sample could have been taken with him, or he could have introdced something modern that would contaminate the sample. Another time we needed to include that a hair was caught in the >1mm sieve. This gives you an idea of how specific we needed to be for this job.
After all of this was recorded, along with all the information about where a sample came from, we collected each section of the sample (small finds, residue, >1mm, >300microns) and stored them where they could dry and be examined later through dry sorting and microscopic examination. We're not going to get to do any of that, unfortunately.
When the sample was cared for, we got to carefully clean every bit of equipment. Even that was fun, because we got to do it with hoses squirting preasurized water. There was  a lot of mud and water in today's job, but I liked it every bit as much as the other jobs I've learned so far.
At the end of the work day, we went back to the site, where we set off on a field trip with the entire American group. Nick, the site director was our guide, which was really neat. He knows a lot of stuff about this, which makes sense, but still... a LOT of stuff.
First we went to the Ring of Brodgar which is in sight of the Ness of Brodgar. The Ring of Brodgar is made up of about 20 standing stones, but it used to have 60, if my memory serves. It is the third largest standing stone circle in the UK. I was surprised at how large it really was. I had thought it was smaller, but I had only seen in on post cards. There was a large circular trench around it which was apparently carved right into the bed rock. That had to be a huge task back in the day. It's not exactly a piece of cake now. We didn't have much time there because we had an apointment for a tour at Maeshowe.
Maeshowe is also within view of the NoB. (All of theseelaborate monuments are right there and it's interesting to think about the implications of their arrangement.) It was originally a Neolithic burrial chamber, but it was used by Vikings, then by the Scottish and various groups. From the outside it looks like a strange hill, surrounded by a grassy trench. The trench here was not as predigious as the one at the Ring of Brodgar, but I still wouldn't have wanted to be the one digging it. It was also carved into the bed rock. The hill had a stone-framed hole in the side, that was about 3'x4' square and that door continued on as a hall-way for about 40' or so. It was akward to maneuver through into the cavern, but it was worth it. (Someone with claustrophobia would nevr have made it.) Inside was very neat. It was... like being on the inside of a hill, but the walls and ceiling were corbelled with large rock. There were four large standing stones in the corners and burrial recesses in the three walls that didn't have the tunnel. There were also neolithic and viking era grafiti on the walls. One of the runed insriptions that was half-way up the wall said something like "I, ----- carved this up so very high" I bet our graffiti will never be treasured as much as this stuff was.
Well, I'm really tired and was hoping to be aslep about 2 hours ago.