They have already been alluded to as occurring by thousands in the Silurian strata unconformably overlying the Cambrian, in the mountain of Queenaig, in Sutherlandshire (Figure 82).
After passing this synclinal line the beds begin to dip in an opposite or north- easterly direction, acquiring a steep dip where they rest unconformablyon the edges of the Upper Silurian strata of the Cobequid Hills, as shown in Figure 447.
The Upper Laurentian or Labrador series lies unconformably upon the Lower, and differs from it chiefly in having as yet yielded no fossils.
The Tertiary strata of that age are seen on both sides of the Rhine, in the neighbourhood of Bonn, resting unconformably on highly inclined and vertical strata of Silurian and Devonian rocks.
Within these limits it occurs in small patches only, resting unconformably on the white chalk.
All these trap- rocks appear to be of Laurentian date, as the Cambrian and Huronian rocks restunconformably upon them.
The Olenellus-fauna has been found near Nuneaton in Warwickshire in beds which unconformablysucceed volcanic rocks, the Caldecote series of Prof.
These Alum Shales, as they are termed, rest unconformably upon Precambrian rocks, and have arenaceous and conglomeratic deposits at the base.
A few fossils belonging to the Olenellus-fauna have occurred in the oldest Cambrian rocks of the Malvern district, and these rocks rest unconformably upon those of an old ridge which is therefore composed of Precambrian rocks.
In the Salt Range of the North-West of India an interesting series of sandstones alternating with limestones rests unconformably upon lower rocks.
They also rest unconformably upon the Ordovician rocks in this area.
As it is followed along the crop it is found to rest unconformably upon the Lower Llandovery, Caradoc, Llandeilo, Cambrian and pre-Cambrian rocks.
At Llandovery they rest unconformably upon Ordovician rocks (Bala), but in many other places no unconformity is traceable.
Tertiary sandstones, inclined from 15° to 30° toward the north and unconformably overlain by Pleistocene gravels.
Unconformably overlying the whole series and in sharp contrast to the fine wind-blown stuff below it, is a third series of coarse deposits about five hundred feet thick.
A greatly deformed and metamorphosed older series is unconformably overlaid by a great thickness of younger strata.
A white to gray sandstone unconformably overlying the red sandstone is shown interpolated between the lowermost and uppermost series, the only example of its kind, however.
The deeply weathered fissile mica schists east of Pasaje (see Appendix C for all locations) are also unconformably overlain by conglomerate and sandstone of Carboniferous age.
The Maritime Cordillera is bordered on the west by Tertiary strata that rest unconformably upon Palaeozoic quartzites.
Upon them have been depositedunconformably a thicker series of deposits, conglomerates, sandstones, and finer wind-blown material.
They are unconformablyoverlain by known Carboniferous at Puquiura in the Vilcapampa Valley (Fig.
Above the red sandstones is a thick series of gray sandstones and silts which makes the top of the section and unconformably overlies the earlier series.
It is one of the most ancient land surfaces on the planet and is coveredunconformably with pre-Cambrian sandstones thousands of feet in thickness, in which the Torridonian Mountains of Scotland have been carved.
The Algonkian In some regions there rests unconformably on the Archean an immense body of stratified rocks, thousands and in places even scores of thousands of feet thick, known as the Algonkian.
They rest unconformably on the Triassic sandstones and the older rocks of the region.
The rocks of this area are known to be pre-Cambrian; for the Cambrian strata, wherever found, lie unconformably upon them.
An erosion surface which thus parts older from younger strata is known as an unconformity, and the strata above it are said to be unconformable with the rocks below, or to rest unconformably upon them.
The formations of the Middle and Upper Cambrian are found resting unconformably on the pre-Cambrian rocks from New York westward into Minnesota and at various points in the interior, as in Missouri and in Texas.
The early Cretaceous sea retired from Texas and Mexico, for its sediments are overlain unconformably by formations of the Upper Cretaceous.
Resting unconformably on these metamorphic rocks, Old Red sandstone strata are met with in a few places.
Let us suppose, for example, that a certain group of formations has been disturbed, upraised, denuded and covered unconformably by a second group.
The Upper Old Red Sandstone rests unconformably on all older formations.
In many instances, the Permian rocks are seen to repose unconformably upon the underlying Carboniferous, from which they can in addition be readily separated by their lithological characters.
There are, however, many more localities in which one would find the Carboniferous rocks resting unconformably upon the Silurians without the intervention of any strata which could be referred to the Devonian period.
It may be wholly wanting, when the Upper Old Red seems to repose unconformably upon the lower division of the series.
Of a somewhat later date than the Maestricht beds is the Pisolitic Limestone of France, which rests unconformablyon the White Chalk, and contains a large number of Tertiary fossils along with some characteristic Cretaceous types.
This break in the life of the two periods is accompanied by a decided physical break as well; for the Gault is often, if not always, unconformably superimposed on the Lower Greensand.
They are strongly folded and are overlaid unconformably by Cretaceous and Tertiary deposits.
Sometimes rests unconformably upon the folded rocks of the Archaen system; but sometimes, according to Loczy, there is no unconformity.
Along the coast lies a belt of granite and schist overlaid unconformably by Cretaceous and Tertiary deposits; inland the mountains are formed chiefly of folded Mesozoic beds, together with volcanic rocks of later date.
Amongst these folded beds lie trough-like depressions filled with the Mesozoic red sandstone which lies unconformably upon the Palaeozoic rocks.
The limestone in turn is unconformably overlaid by the merely tilted sandstone beds at the right of the map.
In the Hudson Valley, it is well known that a considerable disturbance occurred between Cambrian and Silurian time, for there the Medina lies unconformably on the Hudson River shales.
The Chalk again is vertical on the flanks of the Pyrenees, and the tertiary strata repose unconformably upon it.
In one limited region the Caradoc sandstone, a member of the lower Silurian, rests unconformably on the denuded edges of the inferior (or Llandeilo) member of the same group; whilst in some cases both of these sets of strata are upturned.
This Brown-Coal is seen on both sides of the Rhine, in the neighbourhood of Bonn, resting unconformably on highly inclined and vertical strata of Silurian and Devonian rocks.
The inner or eastern ridge farther north of Argentina consists of crystalline rocks with infolded Ordovician and Cambrian beds, often overlaid unconformably by a sandstone with plant-remains (chiefly Rhaetic).
Narrow belts of Old Red Sandstone, resting unconformably on the old platform of slates and schists, have been traced from the north coast at Peterhead by Turriff to Fyvie, and also from Huntly by Gartly to Kildrummy Castle.
The Upper Old Red Sandstone forms a narrow strip on the south side of the Silurian tableland, resting unconformably on the Silurian rocks and passing upwards into the Carboniferous formation.
The Triassic rocks restunconformably on all older formations within the county.
They are often accompanied by volcanic rocks, which are mainly andesitic, and they commonly lie unconformably upon the older beds.
The older rocks are overlaid unconformably by Cretaceous beds, consisting chiefly of sandstones with seams of coal, the whole series thinning rapidly towards the north and thus indicating the neighbourhood of the old shore-line.
The next succeeding deposit is a sandstone, often highly inclined, which rests unconformably upon the Nummulitic beds and resembles the Lower Siwaliks of the Sub-Himalaya (Pliocene) but which as yet has yielded no fossils of any kind.
The whole is overlaid unconformably by the younger Tertiaries of Hundes, which are perfectly horizontal and have been quite unaffected by any of the folds.
There is a curious intermediate type of drainage lately recognized by McGee in the southern states, a superimposed drainage that is not inconsequent upon the buried surface beneath the unconformably overlying surface layer.
The Desert Sandstone beds lie horizontally but unconformably on those of the Rolling Downs, which dip to the south.
Jack, "laid down by this sea; their present position is due to subsequent general upheaval, and they lie directly and unconformably on schists and slates of undetermined age, or on granite or gneiss.
The Permian, as in England, is not involved in the folds which have affected the older beds, and in general lies unconformably upon them.
Their highest beds dip conformably below the Permian rocks at the southern extremity of the coalfield south of Halesowen, and are overlapped unconformably by the Triassic pebble beds at its northern extremity, in the district of Cannock Chase.
Their basement beds rest unconformably upon the Silurian around the flanks of the Dudley Hills, and in the neighbourhood of Walsall.
At the village of Rubery, in an exposure on the roadside, it is seen to be unconformably overlain by fossiliferous Llandovery sandstone, the basement beds of which contain fragments of the underlying quartzite in abundance.
All the Silurian formations from the Mayhill Sandstone to the Ludlow (Aymestry) Limestone are recognisable, but the terminal Downton sandstone is lost below the unconformably overlying Carboniferous.
Callaway, they rise out unconformably from below fossiliferous rocks of Upper Cambrian age.
In the Birmingham District as everywhere in Britain, the Triassic formation rests unconformably upon everything below.
A broad area, lying between the Hollybush sandstone and the unconformably overlying Silurian rocks of Buildwas, is occupied by a series of Upper Cambrian rocks, denominated by Dr.
Round Bridgenorth this division rests unconformably on Permian strata, and is about 650 feet thick.
The basement beds of the Hollybush sandstones (Cambrian) and the Llandovery rest unconformably upon this rock, which has consequently been claimed by some geologists as distinctly of Archean age, representing in part the Laurentian of Logan.
These Cambrian rocks are overlain unconformably by the Coal measures to the west, and by the Keuper beds to the east; the boundary of the area is, however, locally defined by lines of fault.
The coalbearing strata rest unconformably upon the Cambrian below, and pass up conformably into the Permian above.
It may be seen resting unconformably upon the Cambrian quartzite in the village of Rubery, and at Leach Heath.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "unconformably" in a variety of sentences. We hope that you will now be able to make sentences using this word.
