Skip to Content

This cache has been archived.

geoaware: This EarthCache has been archived because it no longer meets the EarthCache guidelines. If you wish to update this EarthCache, please reference the guidelines at www.earthcache.org. Once you have updated your listing, please email the EarthCache Approver at earthcache@geosociety.org.

More
<

Rock Edge Earthcache

A cache by jochta Send Message to Owner Message this owner
Hidden : 5/3/2005
Difficulty:
1 out of 5
Terrain:
1 out of 5

Size: Size: not chosen (not chosen)

Join now to view geocache location details. It's free!

Watch

How Geocaching Works

Please note Use of geocaching.com services is subject to the terms and conditions in our disclaimer.

Geocache Description:

Small nature reserve with easy public access owned by Oxford City Council

An Earthcache is a special place that people can visit to learn about a unique geoscience feature or aspect of our Earth. Earthcaches include a set of educational notes and the details about where to find the location (latitude and longitude). Visitors to Earthcaches can see how our planet has been shaped by geological processes, how we manage the resources and how scientists gather evidence to learn about the Earth. For more information about Earthcaches, visit http://www.earthcache.org/.

Much of Headington is built around old limestone quarries. Only one good exposure of the limestones survive, at Rock Edge (formerly Crossroads Pit), at the junction of Windmill Road and Old Road.

The Wheatley Limestone has been quarried since the twelfth century and Oxford college records indicate its use as early as the thirteenth century. At first, the quarries at Wheatley supplied building stone to many Oxford colleges and to more distant localities such as Windsor Castle. However, after the end of the fourteenth century, new quarries at Headington became more important, and continued to be used into the early nineteenth century, by which time the poor weathering characteristics of the stone had been recognised. The earliest buildings were commonly constructed of 'random rubble' (undressed stone) or only partially dressed rock, often using Coral Rag. Later, sawn blocks of freestone from the Wheatley Limestone was used for finishing exposed surfaces or for entire walls.

The cliff has exposures of Upper Jurassic rock. There are many fragments of coral and fossils including sea urchins, and this pit is thought to have been a former boundary between a coral reef and the surrounding shallow sea. The south end has Coral Rag outcrops, and there is Wheatley limestone at the north end of the cliff.


Geological materials © NERC. All rights reserved. Topography © Crown Copyright reserved.

The geological exposures of the Upper Jurassic Coral Rag at this site enable geologists to reconstruct the environment 145 million years ago. During this period a warm shallow sea covered Oxfordshire, similar to that of the present day Bahamas Banks. At Rock Edge the Coral Rag is rich in fossil remains, derived from corals reefs that formed in the ancient shelf sea.


Oxford as it looked 145 million years ago.

Close examination reveals the presence of two types of limestone, reflecting the close proximity of the reef margin. One variety consists primarily of coarse fragments broken off the reef, whilst the other is finer grained, representing the lime sand that accumulated on the sea bed a short distance from the reef. Actual in situ reefs were previously visible in quarries located a few metres to the south.

Other nearby quarries (click image for larger version).

Magdalen or Workhouse Quarry
N 51° 45.632 W 001° 12.125
Last quarry to be worked

Vicarage Quarry
N 51° 45.357 W 001º 12.046

Wingfield Hospital North Quarry
N 51° 44.994 W 001° 12.551

Wingfield Hospital South Quarry
N 51° 44.894 W 001° 12.436

Windmill Quarry
N 51° 45.060 W 001º 12.293
Traces can still be found at Slade Close. The flats are built inside the quarry, the outline of the quarry can be seen to the east and south of these.


The published coordinates will get you to the nature reserve, you will then need to explore to find the features. Parking is restricted for residents immediately adjacent to the reserve but you can park nearby on The Slade around N 51° 45.110 W 001° 12.327 or N 51° 44.972 W 001° 12.296. Either offer an opportunity to try and spot the quarry remains at Slade Close.

To log this cache please post a picture of yourself next to the cliff and a picture of a sign with this cache's name on it.

Additional Hints (No hints available.)



 

Find...

66 Logged Visits

Found it 63     Write note 1     Archive 1     Post Reviewer Note 1     

View Logbook | View the Image Gallery of 134 images

**Warning! Spoilers may be included in the descriptions or links.

Current Time:
Last Updated:
Rendered From:Unknown
Coordinates are in the WGS84 datum

Return to the Top of the Page

Reviewer notes

Use this space to describe your geocache location, container, and how it's hidden to your reviewer. If you've made changes, tell the reviewer what changes you made. The more they know, the easier it is for them to publish your geocache. This note will not be visible to the public when your geocache is published.