Kerb Stones need to be made of an extremely hard rock that is resistant to erosion and therefore they have been made of an igneous rock like granite in the past and currently are often made of a hard composite material like concrete.
Often old villages, towns and cities have a variety of kerb stones on their pavements and Ashburton is a good example of this. Wandering around its streets you will see granite flagstones reaching right to the pavement edge, as well as all manner of shapes, sizes and colour kerb stones.
Ashburton Marble was extensively quarried from sites such as the Linhay Hill Quarry on the East side of Ashburton and it features in many of the county’s local churches and grand houses. It was used for both cladding and flooring and can be found in the bathrooms of the London Hilton and the foyer of the Post Office Tower. During the latter half of the 20th century Ashburton Marble was widely exported to South Africa, Hong Kong and the United States where, most notably, it was used in the President Roosevelt Memorial in Washington DC. From http://www.devon.gov.uk/geo-devonrocksgeologyguide.pdf
So, given that the only true marbles produced in Britain were quarried in north-west Scotland on the isles of Iona, Tiree and Skye, how come we have Ashburton Marble in Devon?
Ashburton Marble was formed in the Devonian period approximately 416 - 345 million years ago in a shallow tropical sea by the deposition of plant and animal remains on the sea floor which were then compressed. If you look closely you can see fossils contained within it. Although called Marble, Ashburton Marble is not a Marble in the true sense of the word as, although going through the same processes as Marble over many years, it has not undergone the last process of extreme heat which results in the calcite in the rock recrystallising and forming a denser rock, a true Marble. Instead it is in the pre Marble stage of Limestone. It came in a range of colours and was highly prized as the white calcite and red haematite within it produced spectacular coloured patterns which were enhanced by the hard polishing it was able to take.
The headline co-ordinates take you to the junction of West/East Street and Woodland Road, where there are kerb stones of Ashburton Marble on both sides of the pavement for quite a way along the road. The waypoint takes you to outside the Library and Information office where there are kerb stones and a plaque outside the information office made of Ashburton Marble.
Logging requirements:-
Message me via the message centre the answers to the following questions. Please go ahead and log as found after sending the answers and I will contact you to confirm as soon as I can, which may be several days if I am away on holiday. Please be aware that if a "found it" is logged without the answers to the questions being sent to me your log will be deleted.
1. Ashburton Marble isn't a true Marble; what rock is it and what is this rocks connection to Marble?
2. What is the process that is missing in Ashburton Marbles formation that would have made it a true Marble?
3. Look at both sets of kerbstones, (headline co-ordinates and waypointed), and describe the similarities and the differences. Give the reasons for these differences.
4. What is the length, width and visible depth of the last Ashburton Marble kerb stone at the end of the pavement on the left looking down Woodland Road from West Street?
5. A photo of you/your GPS by NON Ashburton Marble Kerb Stones as part of your log would be appreciated, but is not compulsory. Please do not post photos of the Ashburton Marble.