Tuesday, 9 March 2010

A Spoil Heap Wonder

Christmas 2007 came and went and Chris and I were preparing for our holiday to New Zealand in March. This left very little time for anything else and before we knew it we were heading to the other side of the world.

This is not the place for tales of the most fantastic holiday ever, but if you get the opportunity to go to New Zealand then don’t hesitate – just go! I’ve never known anywhere with so much natural contrast on so small a scale (“small” being a little tongue in cheek). Besides, where else can you walk in the forests of Gondwanaland in the present day?

I digress. We returned in early April and by the time I had recovered from the jet lag and settled into the old routines, it was time to head for Misty Bluff for the first field trip of 2008. The weather was unsettled and I was a little unsure what was in store, but the forecast indicated that we would be unlikely to see any rain. Hmmm……

On arrival I wasn’t the first, but the small group of people there looked vaguely familiar and I presumed they had visited before. As I was getting ready Peter and Joyce arrived (the organisers), and within a short time I had signed in and was heading to the Bluff.

I hadn’t seen Mark or Chris in the car park and presumed that they had got in quickly to scour the surface of the quarry, for there had been a new scraping on the north east side and I had been told that the bottom of the quarry and the west bank had suffered “significant change”.

As I walked through the brickworks I could see that the area at the top of the quarry had been thoroughly worked on. Then I realised that I shouldn’t be able to see the quarry at all! Some old buildings at the back of the works had been demolished and cleared making access to the Bluff somewhat easier. I walked to the top of the Bluff and looked down. They had certainly been busy in the winter!

The lake had been dammed and was now about half its original size and water was being pumped from the drier side into the smaller lake. They were preparing to dig deeper, which they had mentioned to us about 18 months previously. The far western end of the quarry had also received tons of overburden and was now partially filled. This wasn’t ideal (from a selfish point of view) but if any part of the Bluff is to be filled, then I’m absolutely certain that this would be everyone’s first choice.

Apart from these changes, the other surprise was that I was the only person there. Mark and Chris had obviously not made it, so it appeared that I had the Bluff to myself for a short period. I wasted no further time and headed to the bone beds of the south east face. There had obviously been no scrape here and I returned to where I was looking during my previous trip as it was here that Chris had found a couple of pieces of bone (by my rucksack if you remember!).

Within a very short time and within a yard of where I had been previously excavating I spotted a piece of bone in a rain worn gulley. It was jet black and I carefully dug into the clay hoping it would carry on into the bed, but was disappointed to find that it did not. I believe it may be a rib section, probably crocodilian, but this needs to be checked. However, I was confident it would be a nice piece when cleaned up and I was happy with my start to the day; the pressure was off.

I scoured the rest of the bed but to no avail and pretty soon the others turned up and the Bluff was being searched in all directions. I made the decision to stay where I had found the bone and started to dig into the clay in the hope of uncovering more. However, I decided to dig about a metre higher than normal, not only because this area seemed to be the “mother lode” for the bone, but also because I had been looking more into the history of the Bluff and it was apparent that the majority of the bones recovered here were in the uppermost beds, particularly the sandstone beds.

On this occasion, however, I was not lucky and the excavation proved fruitless. I decided to move to the recently scraped north east beds and prospect there for a while. At this point it started to rain which progressively got heavier and heavier – so much for the weather forecast! Those of you who have prospected in a clay pit such as the Bluff will know that after a period of rain the clay gets terribly “claggy” and you can hardly move. At one point it looked as if the rain was here to stay but after half an hour it stopped and the surface quality improved enough to continue.

After a break for something to eat, I decided to go and check on those brand new spoil heaps I had seen when I first arrived at the Bluff. Historically, these heaps have thrown up some exceptional fossils, not only here but at quarries throughout the UK. As I approached the biggest of the heaps I felt quite excited because I was fairly certain that nobody else had bothered with them.

As I stood next to the first heap, I suffered from what can only be described as a “sensory overload”. Not only were there every sort of clay and sandstones from the quarry, but this was mixed in with soil and other goodies from around the top of the quarry which meant that separating the ‘wheat from the chaff’ was difficult. However, eventually my eyes adjusted and started to assess the heap.

After about 10 minutes I decided to walk down the most vertical side of the heap in the belief that heavy bone may tumble down to the bottom. What a decision this proved to be because I’d only walked a few yards when I stopped in my tracks and looked, looked around to make sure it wasn’t a joke, and looked again.

There sitting on top of a small pile of clay was a vertebra, the black shiny enamel glistening wet, which looked as if it had been carefully placed there for all to see! This time there was no mistake and I recognised it immediately as a caudal vertebra from Iguanodon sp. Box shaped, the vertebra even has some processes attached, and almost certainly has the neural canal preserved.

Unusually though, the vertebra is also partially encrusted with matrix which appears to be a form of sandstone that, when gently tapped, feels like it is hollow although there are obvious solid elements within it. On the plus side this very same matrix is also the reason that the processes are still there, and for that I am grateful. There are also remnants of insect egg cases in the nooks and crannies and this has led me to the conclusion that this bone had been exposed previously and has been sitting on the site until the bulldozers cleared the area to make the new spoil heap, thus exposing it yet again.

Absolutely thrilled with the find, I placed my prize in my bag and continued the search. Not too surprisingly I found nothing else on the heap but I suspect that at that point I was having problems concentrating! A little later I returned to the main quarry to continue searching and indeed I began to excavate again into the south east bank but to no avail.

I looked at the sky and realised that some substantial rain was heading our way. Discretion quickly became the better part of valour and I headed back to the car. No sooner had I arrived back at the car than the heavens opened up and I probably looked a right sausage trying to take shelter under my tail gate while removing my boots!

I took my leave of the Bluff for another 5 months but, as ever, am keen to return. I just might have a look at that spoil heap again…..


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