175 million years ago…


..dinosaurs plodded through a shallow lagoon, leaving footprints as they went. Thanks to the wonders of geology, the footprints were preserved as limestone, only to be uncovered again in 1994 when the modern limestone quarry was excavated to that level. They are the oldest and best preserved dinosaur prints in the world.

Here is something I don’t understand. A dinosaur steps in mud and a footprint is made as the mud squidges up around the edges and between the toes. I get that bit. What I don’t get is how that footprint remains in place long enough to be preserved as limestone – in CSI, they only have about 2 minutes to ‘preserve the evidence’ if the weather turns bad or whatever. Surely, particularly in a shallow lagoon, the movement of the water would wash the footprints away pretty quickly? Don’t quite understand it myself, but fortunately there are people who do.

I love anything old, so was quite excited to see the prints. A footpath takes you around the top of the quarry so that you have an aerial view of the path that they took. Except, we didn’t exactly. We weren’t really sure what we were looking at and, because of the many holes and fissures left by dynamite before the discovery, you are looking at a pretty pockmarked surface. It’s a bit like looking at a baby scan – you know you are meant to be seeing a baby, but you can’t really make it out.

Down on the floor of the quarry, the prints are clearer but still a bit disappointing. I’m not sure exactly what I was expecting but what I saw wasn’t it. Never mind, at least I’ve ticked a box and seen them and the quarry has a fantastic view so made for a nice walk. And there was a little garden to walk through with one of the best pictorial timelines of the history of Earth that I have seen.

I also learnt something I didn’t know before, thanks to the information boards posted around the walk. I quote – ‘Dinosaurs, who are they? In general terms, they had long members and, unlike other reptiles, these were inserted straight under the body, like in mammals and birds’. Righty ho.

D's favourite bit of the timeline because it shows a man and dog. He grunted when he saw this.

We’ve moved on from Tomar, after staying a day longer than planned. We were going to visit the grounds around Convento do Cristo, but the weather was wet and we were tired after staying up to silly o’clock the night before. So instead we mooched around the van for the day and then went out for drinks with Jim & Becky, a couple we met on the campsite who have been in Portugal for a few months looking for a property. In true Portuguese style, we didn’t go out until about 9.30 and were still about the only people in the bar when we got there. By the time we left a few hours later though, it was packed with people enjoying a drink, coffee or some of the best hot chocolate I have ever tasted – like melted chocolate pudding. Yum. Walking home after midnight, lots of people still around in and out of bars and no-one drunk – a great atmosphere.

S

Comments;

ENGLISH MUM
I envy you the hot chocolate. We had something similar in Croatia. Haven’t yet found a comparable one here, in fact I don’t even try them now because they are invariably too weak. I don’t understand how the footprints were preserved either. Perhaps it’s all a big con!

ENGLISH DAD
I wonder if it would help future palaeontologists if I tried to mark the date with my finger when I walk through squishy places.

ENGLISH DAD
A few years ago I saw some fantastic miniature dinosaur footprints which had been left in Plasticine. Quite remarkable when you think how old they must have been.

AUSSIE DAD AND JAN
S is right. If the squishy stuff was in a sea or river, the footprints would get washed away. If, however, the dinosaur was walking through a primeval marsh the water would be still. The footprint stays there, all being well. Stuff (silt etc) fills it up and preserves its shape. If they are in Limestone, I guess it was a shallow sea. The Limestone is formed from the shells of crusacea that die and fall to the floor; the same process applies for the footprint. Or so I have read. Your footprints look like real dinosaurs; sort of big and thudding. Those I saw in Broome are three-toed, like a big emu or cassowary. I see that your “man and dog” picture has a Cro-Magnon chap looking out at a couple of dhows approaching. He is probably saying “Trouble here Spot”.

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