Herpetocetus skull #3, part 3 - Excavation, Day 2

The next day I returned to the locality, and with the help of my buddy Chris Pirrone, we finished undercutting the pedestal; due to the extreme cohesiveness of the sediment, we were able to undercut the pedestal by 3 inches on all sides - which is generally a rare opportunity; with many other fossiliferous units I've worked in, the side of the pedestal would collapse or calve off into the trench.
Within two hours of arriving, we were ready to begin the jacketing process. Above, you can see the top jacket.

Here's a view from the top of the cliff of the plaster jacket and the hole. You can definitely see that with the size of the hole, I was prepared for something sticking further into the cliff.
Soon after, we flipped the jacket over and I began removing excess rock from the base of the pedestal. After removing several inches, I used a jigsaw to cut off the plaster 'lip' that was left from the base of the pedestal.
Chris Pirrone, with the jacket.
And finally, myself with said jacket. I have more pictures of the completed jacket, but they would give away the location, which I'm not terribly keen on doing. All in all, this excavation totaled about 8 hours. By comparison, the well preserved Herpetocetus bramblei skull I collected nearby in 2007 took about 12 hours of excavation, and four hours of jacket transport. Thanks to the much more convenient location of this fossil, jacket removal and transport took a total of two and a half minutes; the tide was way out, so we were able to walk (comfortably) with the jacket to a conveniently placed set of stairs, and then up. The battle Chris and I waged in July 2007 to get the other Herpetocetus skull off the beach is quite a story, and one that I don't think I've detailed here previously.

Anyway, as I probably already mentioned, this specimen includes the first complete rostrum of
a Herpetocetus ever collected, and will feature prominently in my future studies of this enigmatic fossil mysticete.

Herpetocetus skull #3, part 2 - Excavation Day 1

Unfortunately, when I discovered this fossil in its mutilated state, it was two days before I planned on driving back to MSU at the end of the summer, and my last scheduled day of fieldwork for summer 2009, so it was absolutely out of the question to excavate the fossil then. So, I had to return sometime to excavate it. I didn't have the option of doing so over Thanksgiving, Winter, or Spring Break, so I waited a whole year. As it turned out, not much erosion had occurred locally over since initial discovery; just to make sure, I'd visit the fossil every couple of weeks.

I finally had the time to excavate it in mid August; I had some ambitious plans for my last week of summer in California: Saturday and Sunday up at Lake Tahoe, monday and tuesday excavating the fossil, wednesday at the Santa Cruz Museum of Natural History, Thursday at California Academy of Sciences, Friday at University of California Museum of Paleontology, packing up my car on Saturday, and Sunday thru Tuesday on the road.I found out a couple days before hand I would be able to enable to enlist the help of my longtime friend and avocational paleontologist, Chris Pirrone, a local attorney in the San Jose area. Chris helped me excavate the first Herpetocetus skull (which, if you attended my SVP talk in 2008, was the focal point of that research), and has helped me with a few other excavations in the Santa Cruz area.On Monday I was all by myself removing overburden. Surprisingly, after only about four hours of chopping at the cliff face with a railroad pick, all the overburden was gone. So, I started to carefully remove rock an inch at a time by tapping my clam knife with a rock hammer. Eventually, I found the premaxillae, and was able to determine the angle the rostrum went into the cliff (and, more importantly, the fact that the rostrum did in fact exist). If the rostrum paralleled the cliff face, then it would make for an easier excavation, as I would not need to dig as large a hole. Unfortunately, the rostrum dove in there pretty steeply. Here's what it looked like after the first day of the excavation: admittedly there's not much there - and that's exactly the way I prefer it for an excavation. The more fossil bone you expose during the excavation, the higher the chances of damaging that bone. So it's important to figure out during an excavation what the fossil is, which way it's oriented, and roughly where each feature should be; surprises during excavations are usually made by damaging bone.

I've outlined in red the anterior portion of the rostrum (premaxillae are the skinny medial elements, while the maxillae are the wide lateral elements). I exposed some bits of the premaxillae here and there, but just enough to know 1) the angle of the skull going into the cliff and 2) the tip of the rostrum. Oddly enough, the midline of the rostrum didn't match up with the midline of the skull exposed in the cliff. As it turns out, there was a fracture running obliquely through the rostrum - you can see it, near where the red lines end. It's actually offset by about five or six inches.

To be continued...

Herpetocetus skull #3, part 1 - tragedy and mutilation

Hey folks,
Sorry for being absent over the last month or so; I've spent an inordinate amount of time up at Lake Tahoe with my family (i.e. ~5 trips totaling over 1 month) and the rest of the time I spent collecting thesis data and fossils in Santa Cruz, and working on manuscripts. With regards to the latter, I received preliminary acceptance of two different manuscripts in the space of one week; you'll hear more about these papers later. In mid-July, I wrapped up a manuscript I've been working on for 5 years; I decided I was finished with it, and submitted the damn thing. Within the same day, I re-submitted a manuscript for Palaios that was returned for major revisions. And about a week later, I received preliminary acceptance of a paper for JVP on Plio-Pleistocene fur seals (which had only been in review for a month and a half, and another month for the editorial decision, which must be some sort of world record for JVP).

One of my many projects this summer was to collect and excavate a small mysticete skull I had discovered on my last day of fieldwork last summer (2009). Here's what I saw in the field:
Difficult to make out what it is? Well, I had seen this before, but it was covered up with algae, and I just thought it was a concretion. I want you to look at this picture again, and look for all the broken, mutilated bone in the "trench". Done? Now, I've labeled relevant anatomical structures on the same photo, below.
1= Left zygomatic process of squamosal; 2= foramen magnum; 3= right occipital condyle; 4= supraoccipital shield; 5= left supraorbital process of frontal. Yes, that was a complete mysticete skull, keyword: was. I cannot begin to explain how pissed off I was when I saw this. Even worse, then I realized that I recognized that morphology from somewhere:Yes, it was a complete skull of Herpetocetus bramblei. Here's my beautiful specimen from nearby (which was actually collected properly).

So, I don't know who committed this crime, and I don't want to know who it was. I know who it wasn't - I know a half dozen very experienced, extremely competent amateur collectors in the Santa Cruz area who would have never done something this awful to a fossil. I'm not going to use this as an opportunity to scold, though it would be completely warranted. Instead, if you're reading this - let this serve as a plea:

Please don't do this. There are people who can help. I would love to teach you correct excavation methods. This fossil is now mutilated, and the braincase is completely destroyed, and those features and anatomical data are now lost forever. You can still get help. Please, if you find something like this in the future, just ask someone - I'm perfectly happy to help collect it without destroying the fossil or parts thereof.

Additionally, other collectors who do not know me, or if you don't even do collecting in California, it doesn't matter where you are or the color of your fossil: please avoid this at all costs. There are plenty of people willing to help you. Just please, please back away from the edge. I mean fossil.

Beach panorama

Beautiful sunsets can often be seen along the California coast, especially during the winter. This is about eight photos spliced together; although some weirdness happened due to the waves, it looks alright.

Scotts Valley whale excavation, part 2

Before I continue, I need to give a shout out to Nick Pyenson - Nick initially forwarded Dr. Smith's emails to me, and this project has wasted a third of my summer. No, but seriously, thanks.

After putting the top jacket on, then came the problem of how exactly I was going to A) undercut it and B) actually flip it over. Normally, a trench is cut and then the pedestal is undercut from all sides leaving a pillar of rock underneath, which you can subsequently eliminate and then flip the jacket over. However, this jacket was far too large to do conventionally. And I couldn't really fit tools in all the way around the jacket to really undercut it from all sides.

So, in cases like this, go tunneling! I started two holes and dug and dug until they connected, and then widened them into a larve cavern underneath, and then added a hole on the other side. Problem was, this jacket was so large, I eventually couldn't reach the back wall with my rock hammer, and had to use my large estwing pick to scrape away underneath. Tunneling, by the way, is a good recipe for bloody knuckles.

Here you can see more of the tunnel. Aside from these two small columns, the back part remained as a large pedestal in back; the jacket stuck out from this like a surfboard with two pillars. Once I cut the pillars, I figured it would break the pedestal, and tilt forward.
The moment of truth! This was on the heavy side. Well, nothing happened - the left pillar remained still, but I figured it would fail if given this much weight. Apparently not, however - it just hung like this for several minutes.

When I cut through the other pillar, it shifted almost imperceptibly forward, but I knew at that instant that I had been successful. Then, I found one of the construction workers to help me flip it over and complete the jacket.Here's what it looked like - you can see the overhanging plaster; that's where the crack formed, leaving a little bit of the pedestal back in the hole, which I'll excavate in a separate jacket.

Voila! Here's the completed plaster jacket. It's pretty heavy.

The Coastal Paleontologist returns: Scotts Valley whale excavation, part 1

Hey folks, a lot has been going on recently. First and foremost, I've been busy dividing my time between collecting the last remaining data for my master's thesis, vacationing up at lake Tahoe (very difficult), and editing manuscripts. I hit a milestone yesterday - I submitted two manuscripts in the same day. I've been working like a hound the last few days to wrap up the first manuscript I ever started: a paper on the sharks, rays, fish, and birds from a new vertebrate assemblage in the Purisima Formation, titled: "Non-mammalian vertebrate remains from a new marine assemblage near Halfmoon Bay, California: Implications for the age of the Neogene Purisima Formation west of the San Gregorio fault", which I submitted to the PalArch Journal of Vertebrate Paleontology, an open access journal based in the Netherlands. I've heard they could use some more submissions, so be sure to read Andy Farke's interview with the PAJVP editor Brian Beatty, linked above. If you've got an article ~75% finished, put in a long weekend and submit that beast! The other article, "Mammalian bite marks on juvenile fur seal bones from the late Neogene Purisima Formation of Central California", was originally submitted to Palaios in march, and returned for major revisions, and apparently all I needed were three hours of work to finish it and resubmit it.
One of the first projects I started this summer was to excavate some sort of a whale fossil at a construction site in Scotts Valley. I was contacted early on in the spring by Dr. Roberta Smith, the project's consultant geologist. Oddly enough, Roberta had been in grad school at UC Berkeley in the mid 1960's when folks like Malcom McKenna and Ed Mitchell were there. To make matters stranger, she had also taught at Howard University and worked at the USNM in Washington D.C., where she knew other well known fossil marine mammal workers Clayton Ray and Frank Whitmore (but stopped teaching there long before Daryl Domning started). Anyway, I'm getting off track. The photo above shows the fossil after a day or so of digging. The exposed bones were not ribs or vertebrae, and I didn't care to expose enough of them for a proper ID due to their relative 'softness'. "What are those cinderblocks doing there?", you ask? Read on...

After about a week of day trips and short visits, the trench is nearly completed around the fossil. Bones continue into the back wall, but were too difficult to continue to excavate; I decided that during jacketing, I would try to form a crack across, collect most of it in one jacket, and return to make a second jacket for the rest.

Here you can see why there were cinderblocks in the first couple pictures. They had already put up a retaining wall, and when they found bones, they marked it off and left the retaining wall unfinished. I was able to park only about 8 feet away. This was the weirdest excavation I've ever done.

And here is the top jacket finished! Note that the hammer is way in the foreground; the jacket is much larger than it appears, and is nearly 4' by 4', and weighs between 300 and 400 lbs.

The Coastal Paleontologist will return!

Hey Folks - sorry for the hiatus; I've been rather busy dividing my time between excavating a whale from the Santa Margarita Sandstone, collecting thesis data on the coast, and spending the rest of my time on a beach at 6,000 feet - Lake Tahoe, of course. Sufficiently sunburned (not that bad) and with some neat fossils under my belt, I'll resume quasi-regular posting for the rest of the summer. Sorry for the break; next up - excavating a mysticete braincase from a construction site in the Santa Cruz Mountains.