Search the Community

Last week I visited a new site in the Wutach Valley that a friend had told me about, but after 4 hours of digging and prying and not much to show for it, I decided to call it a day there and spend the remaining few hours checking out a plowed field in the viscinity which usually gave up a few modest finds. But this time I was in luck. The farmer had laid a long furrow on the edge of the field which was exposing a fossiliferously fruitful bed with which I was quite familiar: the Bajocian Macrocephalen-Oolite with among other things lots of Macrocephalites ammonites ripe for the harvest. All I had to do was a bit of hacking and scratching at the surface to get the blocks out. And I wasn't doing any damage to his fields. The only drawback about field finds is that the fossils are often quite weathered and eroded. The acids in the humus react with the ground water and the substances in the fossils, in this case mostly iron and calcite, and eat away at them. In this case it wasn't so bad, though. Quite to the contrary, some really nice sculptures were a result of its work. The chemical reactions over the years have etched out the lobes and septa of the ammonites, creating some really distinctive and colorful patterns. Here's a typical example of a Macrocephalites jacquoti ammonite in this condition. If anyone else would like to show some results of the working of chemical erosion, then please feel free to do so.