War Memorial # 2311 ~ Kennington EarthCache

Kennington War Memorial 

Kennington war memorial is built of Portland Stone and was designed by Captain Thomas Lodge.  Unveiled in 1924, it was to commemorate the Great War casualties of the 1st and 2nd Battalion of the 24th The London Regiment, known as the Queens, our local battalion, based in Braganza St, now New St. Their regimental badge was the Lamb of Lambeth and a flag bearing the cross of St George. The World War One battle honours were carved on the monument and are France, Flanders, Salonika and Palestine. The battalion became the 1st and 2nd 7th The Queens (Royal West Surrey Reg)  and their World War Two battle honours were added at the sides  in 1947.  This is now the local war memorial for all military casualties.  In 2012 it was cleaned and restored with monies raised by the Friends.

Logging Requirements (Questions to Answer)

Compulsory tasks in order to log a find against this EarthCache, you will need to visit GZ and make some observations and then answer some questions and send answers to me via my Geocaching profile or through the Messenger Centre.

Take a look at the stone the memorial is made of, in particular any visible fossils.

1. Identity the fossils you see in the block directly below 1939-1945. What is there shape.

2. Using the information you have gained from tasks 1.  Which bed was the stone formed in?

3. Look at the rear of the monument, are there any signs of weathering. Has it been affected by physical weathering, chemical weathering, or both.

4. Name the Priory built with Portland Stone

5. Also: Include in your log a photograph of you, your GPS or another identifiable item near GZ, taking care not to include anything in the photo that may give away your answers.

Portland Stone.

Portland stone is a sedimentary rock formed in shallow, tropical seas during the Tithonian stage of the Jurassic period, roughly 150 million years ago, and is quarried on the Isle of Portland, Dorset. The quarries consist of beds of white-grey limestone separated by chert beds. It has been used extensively as a building stone throughout the British Isles and notably in major London such as the Palace of Westminster in 1347, the Tower of London in 1349 and the first stone London Bridge in 1350. Exeter Cathedral and Christchurch Priory, also constructed during the 14th Century, are built of Portland stone.

The name Portland Stone refers to a family of closely related limestone variants with differing characteristics rather than a single, uniform rock type. In some types of Portland stone fossilised sea creatures are abundant while in other types fossils are virtually non-existent.

Portland Freestone is an oolitic limestone with variable shell content. To really appreciate the individual ooids they are best viewed through a hand lens or under some other form of magnfication, although if your eyesight is exceptionally good you might be able to make them out with the naked eye.

The Freestone Member

A freestone is a fine grained stone, typically sandstone or limestone, which can be cut easily in any direction without shattering or splitting, properties which make them particulary suitable for building and for carving.

The Portland Freestone Member forms the upper part of the Portland Limestone Formation and comprises four distinct beds, three of which are extensively used for these purposes:

Roach

The uppermost bed of the Portland Freestone Member is known as Portland Roach. This bed represents a shelly beach dominated by shell fossils. Many of the shells, being formed of aragonite, have been dissolved away by acidic groundwater, leaving behind an empty mould or cast of the shell which was once there.

Whitbed

The fossil content in Portland Whitbed can vary quite considerably, being described as shelly at one end of that spectrum and clean when shells are sparse. Fossil rich varieties tend to be heavy in calcite fossils such as shells of oysters and other bivalves as well as patches of the distinctive reef building alga Solenopora Portlandica.

Basebed

The Basebed is often considered to be the finest quality Portland Stone available.

Typically Basebed has a very clean, homogeneous texture with a negligible shell content making it eminently suitable for carving fine detail in deep relief. It is not quite as durable in exposed locations as Whitbed but makes an unbeatable monumental and carving stone for use on very many prestigious building projects.

Fossils

Fossils are any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals, hair and petrified wood.

Fossils are found almost exclusively in sedimentary rocks because the sediments are laid down in such a way that they preserve the living organism's remains, or a cast or mould of its shape during lithification (the process of becoming rock).

Gastropods - Aptyxiella portlandica - found almost exclusively in the roach and commonly known as portland screws because their spirals make them look a bit like screw threads. The shells of this particular gastropod were made of aragonite. Aragonite usually reverts back to calcite, the more stable polymorph of calcium carbonate, during the fossilisation process, unless lithification occurs relatively quickly in which case there is insufficient time to allow the conversion to take place and the aragonite remains in the rock.

Cephalopods - Ammonites - just about the easiest fossilised sea creature to recognise thanks to their coiled shells. Many Ammonite fossils reveal the inner structure of the shell with its multiple chambers separated by walls known as septa with complicated frilled edges which scientists use to identify which particular type of ammonite they are looking at. The image to the right shows an external view of an ammonite fossil, displaying the numerous ridges on the shell, perpendicular to the shell walls.

Bivalves - Liostrea expansa - is a thick-shelled oyster of medium size that grew in a somewhat cup-shaped form. Although unremarkable in appearance, this oyster is quite striking in the Portland Freestone because, like other oysters, it has a shell of bluish calcite which has survived unaltered due to its robust construction of numerous fine calcite layers.
The image to the right shows a cross section through an oyster shell but large collections of shell fragments are quite common in the Whitbed, as shown in the Whitbed example further up this page and in the image at the top of the page.

Weathering

The weathering of rocks is quite simply the breaking down of the stone at the Earth's surface, by action of rainwater, extremes of temperature, or biological activity. It doesn't involve the removal of rock material. There are two main types of weathering:

Physical weathering is caused by physical processes such as changes in temperature, freezing and thawing, and the effects of wind, rain and waves. An example of physical weathering is freeze-thaw weathering, where water expands slightly when it freezes to form ice. The formation of ice can break rocks, as if water gets into a crack into the rock, it freezes into ice, expanding the crack and making it bigger. This process then repeats itself with the crack in the rock getting bigger every time.

Chemical weathering occurs when the minerals within the rocks are chemically altered. Portland limestone, exhibits chemical weathering where fossils become more prominent due to their greater resistance to acid rain. This weathering process, primarily caused by the dissolution of calcium carbonate by acid rain, reveals the fossil remains by leaving them standing out from the surrounding rock.