Hamstead Trip and Mystery Mammal Tibia

[TXV24]

Hi, 

 

I officially finished school forever on Monday so to celebrate my new fangled freedom I decided to spend an afternoon and evening collecting along the Hamstead to Bouldnor coast, so I thought I'd show some of the highlights from the trip. We had very strong winds and some rain here last week so I figured that the beach conditions would be good for collecting, and the Bouldnor Fm. didn't disappoint. I reached the beach at Hamstead point around 1:30pm, and the spring tide was the highest I'd ever seen it. The tide was technically going out but along this coast the tide doesn't actually fall until two hours prior to low tide, which meant that only a small area of beach was exposed and I'd have to wait a few hours until I was able to make a lot of progress along the coast. 

 

I decided to sift through the small patches of shingle exposed to kill the time, which can often produce a lot of smaller bone fragments and teeth, especially those of crocodiles. After a few minutes I'd collected a handful of fish vertebrae from Bowfins and Unidentifiable teleosts, turtle limb bones, some sections of crocodilian or mammalian ribs, and a worn centrum from a crocodilian cervical vertebra (most likely Diplocynodon, the genus to which crocodilian material from the Bouldnor Fm. is referred). I moved on to a new patch further along the still very narrow beach and again turned up fish vertebrae, mammalian tooth roots, small fragments of crocodilian scutes, and excitingly a large distal portion of a mammal phalanx (presumably Bothriodon). 

 

The tide still hadn't moved so I hedged by bets and moved as far as I possibly could hugging the cliff edge. The base of the cliff at Hamstead Point exposes the boundary between the Bembridge Limestone Fm. and Bembridge Marls Mbr. of the Bouldnor Fm. Just above the junction are the Insect Limestone (world famous for it's insect fossils) and the Oyster Bed (a marine in-raid deposit that can produce fish remains) so I gave these beds a look over but unfortunately nothing was weathering out (Hamstead is an SSSI therefore hammering into the cliff is illegal). Finally the tide started to move out, and when it does it moves out very quick, so there was soon a large area of beach to survey and I could begin making my way down the coast. 

 

The finds started coming in thick and fast after that, scores of turtle carapace and plastron fragments (more than 100 in total), crocodilian scutes, mammal teeth, fragments of mammal bones, and much more. The best finds of the trip were by far a large crocodilian cervical vertebra, pre-molars from the anthracothere Bothriodon, and a fragment of crocodilian jaw, again Diplocynodon. But the best by far was a large distal portion of a mammal tibia found lying in the mud a few metres along from the 'Black Band'. As of yet I don't have an ID for the tibia as it is larger than would be expected for Bothriodon. There are numerous other candidates it could be, so I'll research further (if anyone has any suggestions, even if just to an order level, then that would appreciated). It also seems to have provided quite a nice home for a lot marine colonial species and plants which are currently being removed. 

 

I wrapped up the trip at 7pm and headed home, with a nice haul of finds. Now I've got a few months off before I start university I should be hunting much more regularly, all over the Island, so hopefully the summer will turn up some good finds! I'll attach images below, including of the tibia fragment. 

 

Thanks, 

 

Theo 

 

The distal portion of mammal tibia, covered in seaweeds etc. 

 

 

A large cervical vertebra from a crocodilian (Diplocynodon s.p)

 A section of trionychid turtle carapace (Trionyx s.p)

[TXV24]

Distal portion of a mammal phalanx, most likely Bothriodon

 A premolar crown from the anthracothere Bothriodon. 

[ynot]

Nice finds and trip report.

Thanks for sharing.

[gavialboy]

Congrats on the great finds.

 

[JohnBrewer]

Great report and images. I do hope to get there later in the year work permitting.

 

I've taught and exhibited my work at Dimbola Lodge so they pay my expenses. Just as well as the ferry trip is the most expensive £/mile in the world.... I need to speak to them and try and wangle more work from them!