Discovery and Recovery of a Whale Skull in the Ashley River
By Dave Cicimurri
I hope everyone had the chance to get out and make a few dives during the third quarter. I am looking forward to seeing what types of great fossils you’ve discovered. Speaking of discoveries, I want to let you all know about an awesome fossil that was collected back in August. The project was a great collaborative effort between the State Museum, College of Charleston, and licensed divers.
The fossil was discovered by a College of Charleston student, who was living in the Summerville area at the time, while he was out on a kayak run on the upper Ashley River. At low tide the river was shallow and clear enough for him to see the dark brown triangular fossil on the river bottom, and recognized it as a whale skull. He contacted MRD about the find and soon after we began coordinating an effort to recover the fossil. It took some time to get all of the pieces in place, but we needed to step up the pace of planning because the fossil was slowly being destroyed as the water passed over it. We finally made it to the site on a Saturday. The field crew consisted of the discoverer (Craig Garrison), the chair of Archaeology at CoC (Dr. Jim Newhard), myself, the former natural history curator at the State Museum (Jim Knight), and two divers (Cat Sawyer and Jimmy Armstrong).
We met at a boat landing and ferried our gear up to the site, about a 20 minute jaunt upstream. My hope was that the river bottom was soft enough that we could chip into it with rock hammers and shovels to isolate the skull, then break it free in one large block to take back to the State Museum. The river bottom was hard. We spent several hours using hammers and chisels to trench around the skull. When we started the tide had just reached its lowest point and the skull was under less than 10 inches of water, but within minutes the tide was already coming back in. Then our race began to beat the incoming tide and remove the skull before the water was over our heads. The water eventually got deep enough to where we couldn’t see the fossil, but Cat and Jimmy came with their dive gear and they spent time on the river bottom either chiseling away at the rock, or directing our shovels so that we could pry away some rock. When the water got to be about chest high, which was way too high for me, we made a plan to return the next morning to (hopefully) finish excavating.
The next day we got to the boat ramp as the tide was still going out, we quickly loaded up and paddled up to the site. I brought along a large sledgehammer and pry bar, and after a couple of hours of work we were finally able to trench down deep enough to try and pry the block loose. Of course the tide was coming back in the whole time we were trenching, and we needed to pry the block away quickly before the water became too deep. The sledge and pry bar were just the tools we needed, but unfortunately rather than coming out in one big block of matrix, the skull was removed in three smaller pieces. We discovered after the skull came off the river bottom that it was upside down (we were looking at the roof of the mouth the whole time), and I could see that the top of the skull was beautifully preserved within the rock.
Back at the State Museum I spent about 20 hours carefully removing the skull bones from the enclosing matrix. Sometimes the matrix was very soft and I could have scraped it away with my fingernails, but most of the time it was so hard that I had to use a mini air chisel to remove it from the bone. While preparing the fossil, I learned that the skull came up in three pieces because the hardness of the matrix varied, and the matrix was also already fractured and the skull had cracks in it – the skull came apart along those cracks. I let all of the parts dry for several days after they were removed from the matrix and cleaned, and special glues were used to put the pieces back together.
This was my first experience with underwater excavation (10 inches of water counts…) and the fossil wouldn’t have been recovered without the hard work of everyone involved. I certainly learned a few things and had a great time working with the crew. Can’t wait to study this skull in more detail, and hopefully we’ll have the chance to work on another project like this in the future. Keep your eyes open and let us know if you find skulls or skeletons on your dives. Good luck out there.