Now with a whole new batch of trilobites from Penn Dixie (see my blog post on that experience here), it is time to learn how to prep. This will be my first time attempting this. Practicing on less valuable finds is a must at first. I don't have the space to go the full air compressor / vacuum system, so it will just have to be dental picks and a Dremel engraver with a lot of attachments. But here is the work so far.
Here's part of the workspace, nice and outdoors - but it is still important to observer safety (so a dust mask to block out all that very fine rock dust, and eye protection is a must).
Some of the steps in the prep: from initial state, matrix removal, more matrix removal and oil application for testing. There is more to be done to buff out the scratch lines and uncover a bit more of the specimen on the left.
This one below began with a lot of matrix, which I kept removing, leaving this one thumb-holder tag. On the right-hand side, the almost complete roller - just need to get the dental picks into the pleura to scratch off some tenacious matrix bits.
While removing matrix with a hammer and pin, you'll sometimes discover some surprises...
This is just interesting, although specimens are incomplete, yet we have two cephalon moults, in a kind of mirror positioning. Note the detail on the lenses of the schizochroal eye in the bottom one. It is said that such advanced eyes are possibly evidence that these benthic creatures were not scavengers, but active predators. As trilobites continued to develop in an environment with increasing numbers of predators (and the size thereof), they lost such advanced ocular features and most likely became scavengers again. As another possible proof of a predatory lifestyle, the hypostome (conterminant as opposed to natant) on this species (Eldredgeops rana) was far more developed and anchored to the anterior cephalon - a feature most commonly found in such animals as ticks - and their large "noses" (glabella) were like "gastric mills" for digestion more suggestive of predatory lifestyle (see Fortey and Owens, 1999). Some were still particle feeders, but those would be the smaller ones; otherwise, they were equipped with the front-loaded gastric apparatus to consume and digest larger bits of prey.
This dirty little roller is going to need to be freed up a bit more before getting a cleaning. Their ability to enrol was a defensive feature not unique to this species, and can be seen in modern day examples such as sow/pill bugs. The cephalon would form a tight seal with the underside of the pygidium, allowing their tough carapaces to shield their soft underparts.
A complete surprise - a chunk I decided to split revealed a nice little assemblage