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I believe I've already mentioned elsewhere that I do some prep work for an English paleontologist in exchange for raw material which I can work on for my own collection. The last batch he sent me contained among other things a concretion containing an Amaltheus margaritatus ammonite from the well known site at Eype on the Dorset coast. This was a first for me. Although I've worked on a good number of concretions in the past, I had as yet to deal with one from Eype. Here's what it looked like upon arrival. As you can see, it was easy to locate the ammonite, but I was a bit concerned because of the exposure that some weathering had gotten at it. There also may have been some other fossils under the matrix, so I decided to first start off with the abrader to see if I could find anything. It turned out that the surface was too hard to make much noticeable progress, so I turned to the scribe instead. After a bit of laborious digging it became pretty obvious that there wasn't much to find. Since the scribe work had been incredibly tedious, I then decided to give the concretion a well-placed whack, in the hopes that it would split along the lines of a typical Whitby Dactylioceras concreton. The whack was well-placed and thought out, but unfortunately, as I had feared, the ammonite split through the middle of the weathered part. Oh well, you can't win them all . I had made a photo at this stage, but unfortunately I deleted it unwittingly, otherwise I could show you the mess. Fortunately it was a clean break and I could also salvage the couple of little pieces which flew off. So the next step was to remove as much matrix as possible with the diamond edged saw from the broken-off piece and glue it back onto the rest. I also disposed of the negative part of the concretion, which reduced the size of the piece considerably. I used superglue and let it cure for 24 hours. Here's what it looked like before I continued: I took to the abrader again, hoping that I wouldn't necessarily have to use the scribe too much, for fear that the vibrations might loosen things up and managed to get this far, but the matrix was so hard in places that even working with 120psi didn't make the necessary headway. There were also some nasty little pyrite concretions causing problems. So I held my breath and, with a firm grip on the sensitive area, I started scratching away bit by bit until I had reached this stage: The weathering had seeped in between steinkern and shell, causing some loss of shell, but at least the general form was still intact. I then again turned to the abrader to finish it off: I then decided to fill in the gaps with a stonemeal mix, coated it with my favorite beeswax finish and ended up with this result: Amaltheus margaritatus 11cm. Late Pliensbachian margaritatus zone Early Jurassic From Eype, Dorset, UK
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From the album: Cephalopods Worldwide
11cm. margaritatus zone Late Pliensbachian Early Jurassic From Eype, Dorset, UK -