Barail Range: Geography, Geology, Peaks & Biodiversity
The Barail Range is one of the important mountain systems of Northeast India. It forms a series of mountains, high ridges, valleys, and watersheds between the Brahmaputra River and the Barak River. The range extends across parts of Assam, Nagaland, and the adjoining northeastern hill regions.
The landscape of the Barail Range varies considerably, from relatively flat and undulating river valleys to steep mountainous terrain. The range is particularly important for understanding the physiography, geology, forests, wildlife, and biodiversity of Northeast India.
Note: Some older geographical sources use the former name North Cachar Hills (N.C. Hills) for the present Dima Hasao district of Assam.
Barail Range: Geographical Location
The Barail Range is located in the northeastern part of India and constitutes an important physiographic link between the Meghalaya Plateau and the Naga Hills.
A commonly cited location for the Barail hills in Dima Hasao is approximately:
Latitude: 25° 16′ 27″ N
Longitude: 93° 20′ 51″ E
Region: Northeast India
Major states associated with the range: Assam and Nagaland
The Barail Range acts as an important watershed between the Brahmaputra and Barak river systems.
Physiography of the Barail Range
The Barail Range is a Tertiary mountain system that topographically connects the ancient Archaean Meghalaya Plateau with the younger Tertiary Naga Hills.
In Assam, the Barail hills form the western continuation of the Barail system extending from the Nagaland region. The range is especially prominent in Dima Hasao district.
One of its most important geographical characteristics is its role as a divide between two major drainage systems.
Barail Range as a Watershed
The Barail Range divides the hills of the region into two major drainage areas:
Northern part – drains towards the Brahmaputra Basin
Southern part – drains towards the Barak Basin
Several rivers and their tributaries have deeply dissected the range over geological time.
The Kopili River and Dhansiri River, along with their headstreams, have played an important role in modifying the northern slopes through headward erosion. As a result, parts of the northern face have relatively gentle slopes and lower elevations compared with the steeper southern slopes.
Height and Major Peaks of the Barail Range
The elevation of the Barail Range varies significantly. In some areas, the range rises from around 300 metres above sea level, while several peaks rise well above 1,500 metres.
Important peaks associated with the Barail Range include:
| Peak | Approximate Elevation | Location / Mountain System |
|---|---|---|
| Theipibung Peak | 1,866 m | Barail Range (Highest peak in Assam) |
| Mahadeo Peak | 1,739 m | Barail Range, Dima Hasao district, Assam |
| Kaukaha Peak | 1,736 m | Barail Range (near Jatinga / Haflong valley), Assam |
| Hemeolowa Peak | 1,679 m | Barail Range, Dima Hasao district, Assam |
| Tukbai Peak | 965 m | Barail / Cachar Hills region, Assam |
The Theipibung Peak is among the prominent high points of the Barail hills in the Dima Hasao region.
Slope Characteristics
The southern face of the Barail Range is generally steeper than the northern face. This difference is associated with geological structures, including faulting, as well as prolonged erosion and river incision.
Barail Range in Nagaland
The Barail Range also extends into Nagaland, where it forms an important part of the state's mountainous landscape.
The range enters Nagaland from the direction of the former North Cachar Hills region of Assam and extends through the Kohima region. It is connected with other hill systems of Northeast India, including the Patkai Range, through intervening smaller ranges.
The Barail system is therefore part of the broader and complex mountain structure of Northeast India and the Indo-Myanmar mountain region.
Japvo Peak
Japvo Peak, located near Kohima in Nagaland, is associated with the Barail mountain system and rises to approximately 3,014 metres above mean sea level.
The mountain system around Nagaland is characterized by complex ridges, deep valleys, steep slopes, and structural features created by tectonic activity.
The Barail and Patkai mountain systems are interconnected through smaller ranges. Around Kohima and towards Mao in Manipur, the mountain trends change direction, reflecting the complex geological structure of the northeastern hill region.
Geology of the Barail Range
The geology of the Barail Range is closely associated with the Tertiary sedimentary formations of Northeast India.
The rocks of the Barail Group are predominantly sedimentary and commonly consist of:
Sandstone
Shale
Clay
Coal
The sandstones range from fine-grained to coarse-grained varieties. Alternating layers of sandstone and shale give many parts of the Barail Group a characteristic turbiditic appearance.
The term “Barail” was introduced into geological terminology by Evans in 1932.
Barail Group of Rocks
The Barail Group represents sediments deposited during the Oligocene geological period in the evolving geological basins of Northeast India.
The major rock types of the Barail Group include:
Well-bedded sandstone
Shale
Clay
Coal-bearing strata
Coal seams occurring within the Barail Group have economic significance and have historically been exploited in parts of Northeast India.
The Barail rocks are generally separated from the overlying Miocene Surma Group by an unconformity.
Surma and Tipam Groups
The geological history of the Barail region is closely related to the development of several successive sedimentary groups.
Surma Group
The Surma Group consists mainly of:
Sandstone
Shale
Clay
These sediments are largely associated with the Belt of Schuppen, a structurally complex zone of folded and faulted rocks in the northeastern hill region.
Tipam Group
The Tipam Group conformably overlies the Surma Group in many areas. Its rocks are mainly found within the Belt of Schuppen, although they also occur in parts of the eastern high-hill region.
The geological succession reflects repeated episodes of uplift, subsidence, folding, faulting, erosion, and sediment deposition.
Geological Evolution of the Barail Region
The geological development of the Barail region is closely related to the tectonic evolution of the northeastern part of the Indian subcontinent.
Towards the end of the Eocene, major changes occurred within the regional geosynclinal system. The development of troughs and geanticlines created shallow basins in which the sediments of the Barail Group accumulated.
Alternating marine and sub-aerial conditions contributed to the formation of sedimentary sequences, including coal-bearing strata.
During the Oligocene, the emergence of the Barail sediments was associated with significant tectonic changes. Local sedimentary basins subsequently developed, allowing the deposition of the Surma Group.
Later tectonic movements produced extensive folding and faulting. The Belt of Schuppen is considered an important product of post-Barail tectonic activity.
During the Miocene, the uplift of the Naga, Patkai and Lushai hill systems, together with subsidence of adjacent foredeep areas, created conditions favourable for the deposition of the Tipam Group.
Further tectonic activity during the Mio-Pliocene contributed to uplift and deformation across the northeastern region.
The continued interaction between tectonic uplift, erosion, sedimentation and river activity ultimately produced the complex mountainous landscape seen across the Barail region today.
Dihing Group and Quaternary Deposits
Later geological processes resulted in the development of shallow lacustrine and fluviatile basins, where sediments of the Dihing Group accumulated.
Intense tectonic activity and rapid sedimentation contributed to the formation of coarse, pebbly deposits in parts of the Dihing succession.
The Dihing rocks are subsequently overlain in places by Quaternary alluvial deposits. These deposits represent a relatively recent stage in the geological development of the region and are associated with the continuing evolution of the river valleys and floodplains.
Belt of Schuppen
The Belt of Schuppen is an important structural and geological feature of the northeastern hill region.
It is characterized by complex:
Faulting
Folding
Thrusting
Sedimentary formations
Structural deformation
Barail, Surma and Tipam formations occur in different parts of this structurally complex belt.
The geological complexity of the Belt of Schuppen reflects the strong tectonic forces that have shaped the mountain systems of Northeast India.
Biodiversity of the Barail Range
The Barail Range is one of the biologically significant but comparatively less-known ecosystems of Northeast India.
Its biodiversity is largely a result of:
Wide altitudinal variation
High rainfall
Tropical and subtropical climate
Dense forests
Numerous streams and valleys
Varied topography
Connection with larger forest ecosystems of Northeast India
The elevation ranges from low valleys to peaks exceeding 1,900 metres in parts of the Assam Barail hills. This variation creates several ecological zones and supports a diverse range of plants and animals.
The forests of the Barail region have considerable importance for wildlife conservation and bird diversity.
Forests of the Barail Region
The Barail landscape includes forest areas associated with the former:
North Cachar Hills Reserve Forest
Barail Reserve Forest
Unclassified forests extending across parts of Dima Hasao and adjoining areas
These forests form important habitats for numerous species of mammals, birds, reptiles and other wildlife.
The region's forests also provide ecological connectivity between different forested landscapes of Northeast India.
Bird Diversity of the Barail Range
The Barail Range supports a rich variety of birds because of its extensive forests and variation in elevation.
One of the most notable birds associated with the region is Blyth's Tragopan (Tragopan blythii), a rare pheasant of the eastern Himalayas and northeastern hill forests.
Other birds associated with the Barail region include:
Lesser Adjutant (Leptoptilos javanicus)
Swamp Francolin (Francolinus gularis)
Cinereous Vulture (Aegypius monachus)
The area also provides habitat for several winter migrants and species associated with subtropical and tropical moist forests.
The Barail region includes ecological conditions corresponding broadly to Sino-Himalayan subtropical forests at higher elevations and Indo-Chinese tropical moist forests at lower elevations.
Mammals of the Barail Range
The Barail forests are home to a remarkable variety of mammals. The region is particularly important for its primate diversity.
Primates
Seven primate species have been recorded from the Barail region, including:
Slow Loris (Nycticebus coucang)
Stump-tailed Macaque (Macaca arctoides)
Assamese Macaque (Macaca assamensis)
Rhesus Macaque (Macaca mulatta)
Pig-tailed Macaque (Macaca nemestrina)
Capped Langur (Trachypithecus pileatus)
Hoolock Gibbon (Hoolock hoolock)
Taxonomic note: Scientific names used in older references may differ from currently accepted classifications.
Other Important Mammals
The Barail forests support several large and medium-sized mammals, including:
Asiatic Black Bear (Ursus thibetanus)
Tiger (Panthera tigris)
Leopard (Panthera pardus)
Clouded Leopard (Neofelis nebulosa)
Jungle Cat (Felis chaus)
Leopard Cat (Prionailurus bengalensis)
Golden Cat (Catopuma temminckii)
Marbled Cat (Pardofelis marmorata)
Dhole or Wild Dog (Cuon alpinus)
Sambar (Rusa unicolor)
Barking Deer/Muntjac (Muntiacus muntjak)
Wild Boar (Sus scrofa)
Binturong (Arctictis binturong)
Serow (Capricornis sumatraensis)
Gaur (Bos frontalis)
The Asian Elephant (Elephas maximus), once associated with the region, has been reported as locally extinct in parts of the Barail landscape.
Reptiles of the Barail Range
The warm and humid climate of the Barail region provides suitable habitat for a wide variety of reptiles.
Common reptilian groups include:
Lizards
Snakes
Tortoises
The Asian Brown Tortoise or Asian Forest Tortoise (Manouria emys) has also been recorded from the region.
The presence of diverse reptiles further demonstrates the ecological importance of the Barail forests.
Importance of the Barail Range
The Barail Range is important from geographical, geological, ecological and economic perspectives.
1. Geographical Importance
It acts as an important watershed between the Brahmaputra and Barak river systems.
2. Geological Importance
The range exposes important Tertiary sedimentary formations, including the Barail, Surma and Tipam groups.
3. Ecological Importance
Its forests provide habitat for numerous species of mammals, birds and reptiles.
4. Biodiversity Importance
The region supports rare and threatened wildlife, including several species of primates and forest birds.
5. Economic Importance
Coal-bearing formations within the Barail Group have contributed to the mineral-resource potential of parts of the region.
6. Regional Importance
The Barail system forms part of the interconnected mountain landscape linking the Meghalaya Plateau, Assam hills, Naga Hills and the Patkai mountain system.
Barail Range: Quick Facts
| Feature | Details |
|---|---|
| Location | Northeast India |
| Major States | Assam and Nagaland |
| Important Assam District | Dima Hasao |
| Former Name of Dima Hasao | North Cachar Hills |
| Major Function | Watershed between Brahmaputra and Barak basins |
| Geological Age | Mainly Tertiary formations |
| Major Rock Types | Sandstone, shale, clay, and coal |
| Important Peak in Assam Barail Hills | Theipibung Peak (~1,866 m) |
| Important Peak near Kohima | Mount Japvo (~3,014 m) |
| Important Rivers | Kopili and Dhansiri |
| Important Geological Formations | Barail, Surma, Tipam, and Dihing |
| Major Ecological Features | Tropical and subtropical forests |
| Notable Wildlife | Hoolock Gibbon, Clouded Leopard, Tiger, Golden Cat, Asiatic Black Bear |
Conclusion
The Barail Range is a significant mountain system of Northeast India with great physiographical, geological and ecological importance. It forms an important watershed between the Brahmaputra and Barak river basins and connects major physiographic regions of northeastern India.
Its complex geological history is reflected in the Barail, Surma, Tipam and Dihing formations, while its varied elevation, forests and climate support a remarkable diversity of wildlife. The presence of rare birds, several primate species and important carnivores makes the Barail landscape particularly valuable for biodiversity conservation.
For students preparing for competitive examinations such as TPSC, TCS, UPSC, SSC and other state-level examinations, the Barail Range is an important topic under the Geography of Northeast India, Physical Geography of Assam and Geography of Nagaland.
Frequently Asked Questions (FAQ)
What is the Barail Range?
The Barail Range is a major mountain system of Northeast India consisting of mountains, ridges and valleys extending mainly across Assam and Nagaland.
Where is the Barail Range located?
The Barail Range is primarily associated with Dima Hasao district of Assam and extends eastward into Nagaland.
Which two river basins are separated by the Barail Range?
The Barail Range forms a watershed between the Brahmaputra Basin to the north and the Barak Basin to the south.
What type of rocks are found in the Barail Range?
The Barail Group mainly consists of sandstone, shale, clay and coal-bearing sedimentary rocks.
What is the highest peak of the Barail Range?
The answer depends on the geographical extent used. Theipibung Peak, in the Assam Barail hills, is about 1,866 metres, while Japvo Peak near Kohima is about 3,014 metres and is associated with the wider Barail mountain system.
Why is the Barail Range important?
The range is important for its watershed function, geological formations, forests, biodiversity, wildlife habitats and mineral resources.
Which rare bird is associated with the Barail Range?
Blyth's Tragopan is one of the notable rare birds associated with the Barail forests.