Starting Geology in East Yorkshire

by Mike Horne

If you are interested in rocks, minerals and fossils, you will probably want to start your own geological collection. Collecting rocks in the field is fun and it means that you can study them at home, comparing the ones you find with pictures and descriptions in books.

One of the best places to go to start a collection is the Holderness Coast. The coast is being rapidly eroded so nobody is going to mind if you take a few piece of rock home with you. The cliffs are made of 'Boulder Clay' - a mixture of clay and pieces of rock, which was dumped by glaciers at the end of the last Ice Age, when they melted. These Ice Age glaciers had travelled great distances, bringing pieces of rock from a wide area to Holderness.

You can find Rhomb Porphyry from Norway, Shap Granite from the Lake District, metamorphic rocks from Scotland, Red Flint which may have come from Denmark, fossil Belemnites from the Chalk on the bottom of the North Sea, fossil Ammonites from Whitby, Carboniferous Limestone from Northumberland and fossil plants from Scarborough, to name a few. They have all been brought by the Ice to East Yorkshire. So you can collect rocks from all these places without having to visit them.

Some of the rocks are large, one or two metres across; it is hard to think of frozen water being capable of carrying such large boulders over such great distances. Many of the softer rocks are covered with scratches, caused by the different pieces of rock rubbing against each other as they were being carried by the ice. You can also find "rafts" of clay and soft chalk which have been scraped off the bed of the North Sea by the glaciers.

So this is not a bad way to start a collection - you can collect a wide variety of rock types, from a wide geographical area and of a lot of geological periods in just one place. And you don't have to pay for them. In fact there are rocks on the Holderness Coast that you may never have the chance to collect elsewhere. Rare fossil Ammonites of Lower Jurassic age have been found in the Boulder Clay and nowhere else. The Chalk and clay "rafts" do not occur in situ on the land in Britain; the only other way to study these rocks is in a cored borehole from the North Sea Oil Fields.

But you must remember that these rocks in the Boulder Clay are not in their original locality, so you cannot study how they relate to each other. As your collection grows and your knowledge of geology expands, you will want to visit some of the places these rocks came from and then you will be able to study them more closely.

Please remember to be careful when you go our collecting rock samples. Cliff faces (and quarry faces) can be dangerous, so you should always wear a hard hat. Always wear goggles or safety specs when hammering and never hammer under an overhang. If you are carrying out fieldwork alone, make sure that you tell someone where you are going and when you expect to get back. If you are going into quarries or private land, make sure that you get permission from the owner first and follow any safety warnings that they give you.

Be considerate to other geologists when you collect, only collect from loose material at important sites or from sites that are being eroded rapidly. And if you change your mind and stop collecting, please don't throw your collection away - offer it to your local museum, school or university.

copyright Hull Geological Society 2021