The Elfas is a range of hills up to in the districts of

Holzminden Holzminden (; nds, Holtsminne) is a town in southern Lower Saxony, Germany. It is the capital of the district of Holzminden. It is located on the river Weser, which at this point forms the border with the state of North Rhine-Westphalia. Histor ...

and

Northeim Northeim (; nds, Nuurten) is a town in Lower Saxony, Germany, seat of the district of Northeim, with, in 2011, a population of 29,000. It lies on the German Half-Timbered House Road. History Northeim is first mentioned in 800 in a document ...

Lower Saxony Lower Saxony (german: Niedersachsen ; nds, Neddersassen; stq, Läichsaksen) is a German state (') in northwestern Germany. It is the second-largest state by land area, with , and fourth-largest in population (8 million in 2021) among the 16 ...

(

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

). Its name is derived from the Lower Saxon word ''Fast'', which means an area of upland that descends on two sides.

Geographical location

The Elfas is located in the middle of the

Leine Uplands The Leine Uplands (german: Leinebergland, ) is a region in Germany's Central Uplands which forms a part of the Lower Saxon Hills and lies along the River Leine between Göttingen and Hanover. It borders on the Weser Uplands in the west, the Inne ...

between the Hils to the north, the

Homburg Forest The Homburg Forest (german: Homburgwald or just ''Homburg'') also known as the Homburg Hills (''Homburger Berge'') is an area of upland up to in the north German state of Lower Saxony. Geography The Homburg Forest is located in the district o ...

to the west, the Hube to the east, the Amtsberge to the south-southwest and the Holzberg to the southwest. It lies not far southwest of Eschershausen and east of

Stadtoldendorf Stadtoldendorf is a town in the center of the Holzminden district, Lower Saxony, Germany. Stadtoldendorf is the seat of the ''Samtgemeinde A ''Samtgemeinde'' (; plural: ''Samtgemeinden'') is a type of administrative division in Lower Saxony, ...

; the town of Einbeck is about 12 km southeast of the Elfas. The B 64 federal highway runs past the Elfas to the north linking Eschershausen with Einbeck. The rounded summits of the Elfas are covered by

acidic soil Soil pH is a measure of the acidity or basicity (alkalinity) of a soil. Soil pH is a key characteristic that can be used to make informative analysis both qualitative and quantitatively regarding soil characteristics. pH is defined as the n ...

beech forests.

Geology

The Elfas is mainly composed of

sandstone Sandstone is a clastic sedimentary rock composed mainly of sand-sized (0.0625 to 2 mm) silicate grains. Sandstones comprise about 20–25% of all sedimentary rocks. Most sandstone is composed of quartz or feldspar (both silicates ...

s from the Bunter sandstone period. As the result of a halokinetic process, which had already been concluded in the

Palaeogene The Paleogene ( ; also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period and system that spans 43 million years from the end of the Cretaceous Period million years ago ( Mya) to the beginning o ...

period, the Elfas fault block migrated in a north-easterly direction towards the

Solling The Solling () is a range of hills up to high in the Weser Uplands in the German state of Lower Saxony, whose extreme southerly foothills extend into Hesse and North Rhine-Westphalia. Inside Lower Saxony it is the second largest range of hills ...

, whereby the mountain-building sandstone rode up over a layer of saliniferous rock of the

Zechstein The Zechstein (German either from ''mine stone'' or ''tough stone'') is a unit of sedimentary rock layers of Middle to Late Permian (Guadalupian to Lopingian) age located in the European Permian Basin which stretches from the east coast of Englan ...

. In the course of this process, mainly older rock strata that had hitherto lain underneath, were overthrust. Out of the subsequent erosion processes today's scarpland emerged as the northern boundary of the Einbeck-Markoldendorf Basin. Geologists in the Weser Uplands also use the terms Elfas Axis (''Elfas-Achse'') or Elfas Fault (''Elfas-Überschiebung'') for the regional fault line, as well as the term ''Elfas Saddle''.

Hills

The hills in the Elfas include (heights in metres above NN): * Helleberg (409.6 m) * Ahrensberg (405 m) * Kneppelberg (386.0 m) * Birkenberg (366.4 m) * Vorwohler Berg (360.2 m) * Moosberg (344.7 m) * Eichholzberg (341.5 m) * Döhrenberg (307.1 m) * Eimer Berg (ca. 300 m) * Kurzeberg (299.0 m) * Böhneberg (290.0 m) * Heisennacken (267.0 m) {{colend

Streams

The streams of the Elfas include: * Allerbach (eastern tributary of the Bewer) * Bewer (northern tributary of the

Ilme The Ilme is a left-bank, western tributary of the River Leine in Lower Saxony, Germany. It is long. The river begins at the pond in the centre of the Solling hills at an elevation of and flows initially northwards to Dassel, then in an eas ...

) * Hillebach (northern tributary of the Krummes Wasser) *

Lenne The Lenne is a tributary of the river Ruhr in the Sauerland hills, western Germany. It has caused flooding in recent years. Having its source on top of the ''Kahler Asten'' near Winterberg in an intermittent spring at an elevation of , the Len ...

(passes the Elfas to the west)

References

Georg Schambach
Wörterbuch der niederdeutschen Mundart
1858, p. 257 Axel Herrmann, Carsten Hinze, Volker Stein: ''Die halokinetische Deutung der Elfas-Überschiebung im südniedersächsischen Bergland'', in: ''Geologisches Jahrbuch 84'', 1967, pp. 407ff. Central Uplands Hill ranges of Lower Saxony Natural regions of the Weser-Leine Uplands Holzminden (district) Northeim (district)