BUNTER

bunter, the name applied by english geologists to the lower stage or subdivision of the triassic rocks in the united kingdom. the name has been adapted from the german _buntsandstein, der bunte sandstein_, for it was in germany that this continental type of triassic deposit was first carefully studied. in france, the bunter is known as the _gres bigarre_. in northern and central germany, in the harz, thuringia and hesse, the bunter is usually conformable with the underlying permian formation; in the south-west and west, however, it transgresses on to older rocks, on to coal measures near saarbruck, and upon the crystalline schists of odenwald and the black forest. the german subdivisions of the bunter are as follows:--(1) _upper buntsandstein_, or _rot_, mottled red and green marls and clays with occasional beds of shale, sandstone, gypsum, rocksalt and dolomite. in hesse and thuringia, a quartzitic sandstone prevails in the lower part. the "rhizocorallium dolomite" (_r. jenense_, probably a sponge) of the latter district contains the only bunter fauna of any importance. in lorraine and the eifel and saar districts there are micaceous clays and sandstones with plant remains--the _voltzia_ sandstone. the lower beds in the black forest, vosges, odenwald and lorraine very generally contain strings of dolomite and carnelian--the so-called "carneol bank." (2) _middle buntsandstein-hauptbuntsandstein_ (900 ft.), the bulk [v.04 p.0802] of this subdivision is made up of weakly-cemented, coarse-grained sandstones, oblique lamination is very prevalent, and occasional conglomeratic beds make their appearance. the uppermost bed is usually fine-grained and bears the footprints of _cheirotherium_. in the vosges district, this subdivision of the bunter is called the _gres des vosges, _or the _gres principal_, which comprises: (i.) red micaceous and argillaceous sandstone; (ii.) the _conglomerat principal_; and (iii.) _gres bigarre principal_ (=_gres des vosges_, properly so-called). (3) _lower buntsandstein_, fine-grained clayey and micaceous sandstones, red-grey, yellow, white and mottled. the cement of the sandstones is often felspathic; for this reason they yield useful porcelain clays in the thuringerwald. clay galls are common in the sandstones of some districts, and in the neighbourhood of the harz an oolitic calcareous sandstone, _rogenstein_, occurs. in eastern hesse, the lowest beds are crumbly, shaly clays, _brockelschiefern_. the following are the subdivisions usually adopted in england:--(1) upper mottled sandstone, red variegated sandstones, soft and generally free from pebbles. (2) bunter pebble beds, harder red and brown sandstones with quartzose pebbles, very abundant in some places. (3) lower mottled sandstone, very similar to the upper division. the bunter beds occupy a large area in the midland counties where they form dry, healthy ground of moderate elevation (cannock chase, trentham, sherwood forest, sutton coldfield, &c.). southward they may be followed through west somerset to the cliffs of budleigh salterton in devon; while northward they pass through north staffordshire, cheshire and lancashire to the vale of eden and st bees, reappearing in elgin and arran. a deposit of these rocks lies in the vale of clwyd and probably flanks the eastern side of the pennine hills, although here it is not so readily differentiated from the keuper beds. the english bunter rests with a slight unconformity upon the older formations. it is generally absent in the south-eastern counties, but thickens rapidly in the opposite direction, as is shown by the following table:-- +----------------+----------------+---------------------+ | lancashire and | | leicestershire and | | w. cheshire. | staffordshire. | warwickshire. | +----------------+----------------+---------------------+ |(1) 500 ft. | 50-200 ft. | absent | |(2) 500-750 ft. | 100-300 ft. | 0-100 ft. | |(3) 200-500 ft. | 0-100 ft. | absent | +----------------+----------------+---------------------+ the material forming the bunter beds of england came probably from the north-west, but in devonshire there are indications which point to an additional source. in the alpine region, most of the trias differs markedly from that of england and northern germany, being of distinctly marine origin; here the bunter is represented by the _werfen beds_ (from werfen in salzburg) in the northern alps, a series of red and greenish-grey micaceous shales with gypsum, rock salt and limestones in the upper part; while in the southern alps (s. tirol) there is an upper series of red clays, the _campil beds_, and a lower series of thin sandstones, the _seis beds_. mojsisovics von mojsvar has pointed out that the alpine bunter belongs to the single zone of _natica costata_ and _tirolites cassianus_. fossils in the bunter are very scarce; in addition to the footprints of _cheirotherium_, direct evidence of amphibians is found in such forms as _trematosaurus_ and _mastodonsaurus. myophoria costata_ and _gervillea murchisoni_ are characteristic fossils. plants are represented by _voltzia_ and by equisetums and ferns. in england, the bunter sandstones frequently act as valuable reservoirs of underground water; sometimes they are used for building stone or for foundry sand. in germany some of the harder beds have yielded building stones, which were much used in the middle ages in the construction of cathedrals and castles in southern germany and on the rhine. in the northern eifel region, at mechernich and elsewhere, this formation contains lead ore in the form of spots and patches (_knotenerz_) in the sandstone; some of the lead ore was worked by the romans. for a consideration of the relationship of the bunter beds to formations of the like age in other parts of the world, see triassic system. (j. a. h.)