Hesselberg
Hesselberg is the highest point in Middle Franconia and the Franconian Jura and is situated 60 km south west of Nuremberg, Germany. The mountain stands isolated and far from the center of the Franconian Jura, in its southwestern border region, 4 km to the north west of Wassertrüdingen. The mountain's first recorded name was Öselberg, which probably derived from öder Berg. This name later changed to Eselsberg and finally to the current name Hesselberg. As a butte the mountain provides an insight into Jurassic geology. It has also witnessed an eventful history, many incidents were handed down from generation to generation and these mixed with facts have become legends. Nowadays many people visit Hesselberg in order to enjoy nature and the wonderful vista. When the weather is clear the Alps 150 km away can be seen.Shape, location, and dimension
The mountain has a length of approximately 6 km and an average width of 1 to 2 km. All of its slopes except for those on the southern side are covered with coniferous or mixed forest. On the upper slopes, and especially on the eastern slope of the Röckinger mountain, there are large areas of deciduous forest. The upper part of the prominent southern side is free of forest. On the southern and north-eastern slopes there are large areas of neglected grassland with their typical juniper bushes. Hesselberg can be divided into 5 sections along its center-line.
- On the western slope there is mainly coniferous forest. This is the starting point for the geological nature trail.
- The western plateau, also called Gerolfinger mountain, has an especially unspoilt appearance with its sinkhole-like depressions, hedges and shrubs. The depressions were, however, not formed naturally, they are the result of mining of material for road construction and lime burning.
- Since 1994 the central part, known as Ehinger mountain, with the main peak and the transmitter tower has been accessible again; previously there was a restricted military area of the United States Army here.
- The woodless eastern plateau, which is called Osterwiese or Röckinger mountain is the most important area for tourism. This section serves as a launching zone for model planes and hang-gliders and as an observation platform. On especially clear days one can see the Zugspitze in the Alps can be seen.
- The highly afforested eastern foothill, known for its legends, has the name Schlössleinsbuck. This small hill top is also called Small Hesselberg. The Röckinger mountain and the Schlössleinsbuck are separated by the Druid's valley.
Hesselberg is amongst the most important geotopes in Bavaria. On 24 September 2005 it was awarded the cachet Bayerns schönste Geotope by Georg Schlapp in the course of a ceremony.Jurassic origin
200 million years ago the Jurassic sea extended from the North Sea basin far to the South and covered the late Triassic land. At that time the Hesselberg region was on the border of that sea. Many affluxes brought huge masses of rubble from the eastern mainland and formed a multilayer seafloor, which had a rich flora and fauna. During more than 40 million years the different layers of Jurassic rock consecutively deposited: the Black Jurassic at the bottom, the Brown Jurassic above, and the White Jurassic at the top. Each of these layers is characterised by the typical rock and embedded fossils that are specific for each era. Because certain fossils are solely found in certain layers, they are referred to as index fossils. In Jurassic rock ammonites are the index fossils. In the course of time the Jurassic sea silted up completely. Because during the Early Jurassic Hesselberg was located in a sheltered basin it was not as eroded by wind and water as the plain between the mountain and the Hahnenkamm. The hard rock resisted erosion and left Hesselberg as a distinctive Zeugenberg rising above the landscape like an island. This kind of mountain-formation is known as inverted relief.There is a geological nature trail on the mountain with signs that describe its origin. Each of the three main parts of the Jurassic era is divided into six sub-divisions, which are numbered with Greek letters alpha to zeta. The rocks that are found in the different layers are assigned to this classification.Early Jurassic (Lias) layers
The Black Jurassic is so called due to the dark colours of clay and marl characteristic of this era. This layer is approximately 50 m thick and forms the fertile hilly area around the mountain. Its lowest sub-layers are beneath the surface. The Amaltheenton at 35 m is the thickest sub-layer of the Lias. A special feature is the Posidonia schist, which is 10 m thick. In this sub-layer fossils from larger animals are also found such as ichthyosaurs. The cavity of the Posidonia schist, which is at the starting point of the nature trail, is a unique natural geological monument where it is prohibited to search for and to collect fossils. Above these well visible schist layers lies the Jurassic marl, which is 2.7 m thick.Middle Jurassic (Dogger) layers
The dark brown colours of the weathered upper layers give the name to the Brown Jurassic. The colours are a result of highly concentrated iron. The layer of the Dogger which is 135 m thick forms the main part of Hesselberg's slopes. The lowest sub-layer is formed of 75 m thick Opalinus-clay. The soil of these layers is very susceptible to landslides which has resulted in the unevenness of the meadows. On top of the Opalinus-clay lies a layer of iron sandstone, which is 40 m thick. This layer is very distinctive due to its steep rise. Because the Opalinus-clay layer is impervious to water, a spring horizon has formed at the transition to the iron sandstone. The layers of Dogger gamma , Dogger delta , and Dogger epsilon are summarised under the term "ooliths". These layers contain many fossils. On the very top of the Middle Jurassic layers is the Ornate's clay layer, which is only 2 m thick. This small layer forms a terrace around the Hesselberg. On its southern side the buildings of the folk high school were constructed.Late Jurassic (Malm) layers
The topmost Jurassic layer is called the White Jurassic due to its light colour. These layers can be up to 400 m thick in the Franconian Jura, but at Hesselberg they are mostly ablated; only 85 m is left. The rocks of the Malm are partly sediments and partly formed from reefs of ancient sea sponges. This rock is widely distributed on the main peak. The light-coloured lime of the White Jurassic was a popular building material for houses and for road construction. The depressions on the western plateau are caused by these excavations. The lowest layers form the Impressa-layers, which are approximately 25 m thick, and the Bimammatum-lime. The old name of the Planula-lime is factory lime, which indicates the use as building material. This layer, which is 15 m thick and interspersed with sponge reefs, forms the plateau of the Osterwiese. The small quarry below the main peak consists of Planula-lime in its lower part, and the Ataxiocerate's layer in its upper, which builds up the main peak and is 20 m thick. The top layer of Malm gamma and the layers of Malm delta to Malm zeta have already been eroded away on Hesselberg.History of colonisation and important incidents in the Hesselberg region
There are illustrated charts in some of the parking lots of the region which provide an insight into the area's settlement history.Hesselberg was used as a shelter and dwelling in prehistoric times. Archaeological artefacts from the Stone Age have been found mainly on the Osterwiese. In the Bronze Age it was constantly settled. In the Urnfield time the colony at the plateaus was surrounded with curtain walls, and moats. Even today the 5 km long remains of the border walls around the Osterwiese, the Ehinger mountain, and the Gerolfinger mountain provide an idea of the importance of these fortifications. Behind this sheltering stonework an important political, economic, and religious center evolved. For a long time these constructions were thought to be of celtic origin, but only one artefact from the La Tène period indicates any Celtic involvement. In the restless Migration Period and during the Middle Ages the walls of Hesselberg were used as a shelter and for defensive purposes. The city museum of Oettingen and the museum for pre- and early history in Gunzenhausen contains many exhibits such as tools and weapons.Romans
Under the rules of emperors Domitian and Hadrian the Romans pushed the border of their province Raetia farther to the North. They expanded the wall of Limes in order to protect against the Germanic peoples and equipped it with many watchtowers, and in the immediate vicinity of Hesselberg large Castella were built. Under the rule of emperor Caracalla the last and widest extension of the Limes took place. To the west of the mountain the wall crossed the rivers Wörnitz and Sulzach in a north-south direction. A few kilometres to the north of Wittelshofen it turned eastward. Due to this sharp bend the strategically important Hesselberg was included within the Roman Empire. There were Castella at Aufkirchen, Ruffenhofen, Dambach, and Unterschwaningen. Castellum Ruffenhofen was the largest in the Hesselberg area. No Roman buildings have been found by archaeologists on the mountain itself. The remains of the Limes now form stone ridges hidden in the woods. Nowadays most of the civil and military wall remains are hidden beneath the ground of local meadows and fields. On top of Castellum Ruffenhofen a Roman park is built. In the local museum of Weitlingen there are a few Roman exhibits.