Old Rags at Dryhill. EarthCache

Please Note :- Both specimen collecting and attacking rocks with a hammer is banned !!! Please do not damage or deface any of the Rocks here !!!

Situated in the Kent Downs is an area of Outstanding Natural Beauty, Dryhill is a Site of Special Scientific Interest (SSSI). The exceptional structure of its rocks and fossils led to it becoming the first 'geological' Local Nature Reserve in Kent.

The site was once a stone quarry that was closed in the 1950s. Since then, nature has reclaimed the site, creating woodlands that are ideal for picnics, family visits and amateur geologists.

The rocks at Dryhill are of great research and educational value as they allow geologists to understand the environmental conditions that existed during the Lower Cretaceous Period, an important part of our geological history.

Exceptional rock formations exposed on the site are called Hythe Beds. Quarrying exposed the rocks of hard, sandy limestone and loosely cemented sandstone also rich in the green mineral, Glauconite. Glauconite is an iron potassium phyllosilicate (mica group) a mineral with very low weathering resistance and very friable. Its name is derived from the Greek glaucos meaning 'gleaming' or 'silvery', to describe it's appearance, presumably relating to the sheen and blue-green colour of the sea's surface. Its colour ranges from olive green, black green to bluish green. It is normally found in dark green rounded pellets with the dimension of a sand grain size. It can be confused with chlorite (also of the same colouring) or with some other clay minerals.

Normally, glauconite is considered a diagnostic mineral indicative of continental shelf marine depositional environments with slow rates of accumulation. For instance, it appears in Jurassic/Lower Cretaceous deposits of greensand. It can also be found in sand or clay formations, or in impure limestones and in chalk. It develops as a consequence of diagenetic alteration of sedimentary deposits, bio-chemical reduction and subsequent mineralogical changes affecting iron-bearing micas such as biotite, and is also influenced by the decaying process of organic matter degraded by bacteria in marine animal shells.

Glauconite forms under reducing conditions in sediments and such deposits are commonly found in nearshore sands, open oceans and the Mediterranean Sea, but not in the Black Sea or in fresh-water lakes.

Glauconite has long been used in Europe as a pigmentation agent for artistic oil paint, especially in Russian "icon paintings". It is also found as mineral pigment in wall paintings from the ancient Roman Gaul. Glauconite is also a common source of potassium in plant fertilizers.

The Hythe Beds are part of a suite of lower Cretaceous rocks that occur in the South East of England. The Hythe Beds were originally laid down as sediments in shallow seas million of years ago. The Hythe formation also contains a softer sedimentary rock called Hassock which occurs in beds that alternate with those of the Ragstone.

Kentish Ragstone is a hard, grey, sandy limestone that forms an important component of the Hythe Formation. Kentish Ragstone outcrops in various places, notably at the cliffs of Hythe and along the Greensand Ridge. Maidstone and Sevenoaks sit on Ragstone, where the Ragstone is of superior quality to that found in other areas of the Hythe beds. This is because the Ragstone beds are uniform in their lithology and present a continuous strata of fine grained grey or blue compact limestone.

Hassock is very soft, more like soil and the Kentish Ragstone is very hard and contains lime mud, sand, fossil material and glauconite, all cemented together - usually by the transparent mineral calcite.

Ragstone and Hassock occur in bands of between 15cm and 80 cm, and the difference in colour between them gives the quarry faces a striped appearance.

The Ragstone (being very hard) is peculiarly suited for medieval work. It is often laid as uncoursed work, or random work, sometimes as random coursed work. Ragstone, a dull grey stone, is still quarried on an industrial scale close to the Kent Downs. It has traditionally been used as a road stone, cobble or sett and a walling block. Although difficult to ‘dress’ with a regular face it has been used as rectangular blocks for the construction of walls and buildings and was very popular for the construction of 19th century churches. More frequently, owing to the difficult and variable nature of the stone, it is seen as self faced irregular blocks in walling. Due to its irregular shape, as with flint, ragstone has been set within brick quoins and bands. ‘Spalls’, fist sized irregular chips of ragstone, have been used to surface paths but modern usage of ragstone is as a general construction aggregate, including fill for gabions and loose or partly binding.

This Earth Cache has been placed here with the kind permission of the Head Ranger of Kent County Council, Country Parks Department and also from the Sites Administrator, English Nature.

N.B. Persons visiting this site are requested by English Nature to respect the Geological features of the Site and take appropriate care on the SSSI. Also take care so as to avoid possible injuries and take care so as not to damage the rock exposures on the site.

In order to complete this Earth Cache you will need to visit the The Dryhill Country Park Site and find 3 different sites within the area.
There is also plenty of parking here.

The picnic site car park is open from 8.30am until dusk but you are able to come into the area outside these times, parking then can be on the roadside at the entrance.

You need to answer the following questions and email your answers to me, via my Profile.

Please feel free to log as found once you have the answers but any logs without an email to myself (with the information required) will be deleted !!!

There is no need to climb on the Rocks to get any of the answers to the questions.

Good luck and Enjoy.

Although it is now not a requirement of logging an Earth Cache, photographs are optional and I cannot request these to be posted. But a photo speaks a thousand words.... so if you have a nice photos of any combination of you, your GPSr and the Old Ragstone at any of the sites, I hope you will choose to post to the cache page by adding it to your log.

This would be great if you could !!!

1 = How long ago were the deposits of Hythe Beds containing the Ragstone laid down ??

Now go to Site1 - The Ragstone Cliff Face - N 51’ 16.611 , E 000’ 08.733

2 = What Angle and direction are the rock layers dipping ???

3 = What height elevation are you at the bottom of the Cliff face? Estimate the height of the cliff here.

4 = Looking at the un-weathered part of the cliff close up, the rocks have a slight tint of colour to them. Why is the hint of colour present in the rock here ??? and What colour do you see ???

Now go to Site2 - The Syncline - N 51’ 16.560 , E 000’ 08.978
5 = Estimate the Depth of the Syncline.

6 = What is the width of the largest layer of Hassock between the layers of Ragstone? Also, what is the width of the layers of Ragstone either side of the Hassock???

7 = What Angle and direction are these layers of Ragstone here dipping ???

OK. That’s it and we do hope you have managed to get some answers and enjoyed your visit to Dryhill and maybe learned a little about the rocks here at the same time.

Thank you and we look forward to your logs.