Oswaldkirk lies in a sheltered position under the hill with natural springs of water. This has made it an ideal place to live for probably hundreds of years. Gradually people might have inhabited the area after the end of the last Ice Age, ten thousand years ago.

Our part of the world has been described  in these words: `Over one hundred million years ago, in the Jurassic period, most of Yorkshire was under a shallow sea with various layers of silt, sand, shale and clay. This was the age of monstrous marine reptiles of the Ichthyosaurus and Plesiosaurus type. They may have hunted over this area.

The layer over the clay is Coralline Oolite (Coral Rag) and is composed of alternate layers of coarse shelly limestone, full of fossils and a hard flinty limestone known as calcareous grit. Exposures of this limestone can be found in quarries in the Oswaldkirk Hag, and fossils, especially the snail types, gastropods, are often found in local gardens and fields.

Ammonite from Old Post Office garden.

Then at the bottom of the sea was deposited a dark slaty clay, the Kimmeridge clay. Changes happened in the earth’s crust and there appeared a great double fault  system of the Coxwold - Gilling Gap. Two faults ran east and west at about the level of Oswaldkirk and Gilling, the strata along this line snapped and the space between then sank down. The valley became quite flat before opening out to the vale of Pickering.     

In more recent times in the Ice Age glacial sheets, unable to over-ride the Cleveland Hills, swept round both sides, blocking the outlet of the rivers to the east. Another glacier skirted the Hambledon Hills and dammed the Ampleforth valley. Then the vale of Pickering was blocked up and filled with water.'

This information is taken mainly from “ The Ampleforth Country”  First Edition. Helen Goodman