In the south the deposits, from the Trias to the middle Eocene, consist mainly of limestones, and were laid down, with a few slight interruptions, upon a quietly subsiding sea-floor.
Pieces of amber torn from the sea-floor are cast up by the waves, and collected at ebb-tide.
in depth, which renders it scarcely possible that they were deposited in a continuous area, for such an enormous depression of the sea-floor could hardly have occurred since Miocene times without involving also Christmas Island.
The sea floor is here rent by a chasm, known as the "Bottomless Pit," the waters having a depth of 65 ft.
That these animals were widely distributed in former times is proved by their occurrence at the present day in palaeozoic fossiliferous strata both of the northern hemisphere and of Australia; and despite the fact that their remains have not been found in rocks of the Mesozoic or Kainozoic epochs, it was conceived to be possible that living specimens might be dredged from the sea-floor during the exploration of the ocean depths undertaken by the "Challenger" expedition.
This knob or ridge may be appropriately regarded as an ancient physiographic fossil, inasmuch as, being a monadnock of very remote origin, it has long been preserved from the destructive attack of the weather by burial under sea-floor deposits, and recently laid bare, like ordinary organic fossils of much smaller size, by the removal of part of its cover by normal erosion.
Annelids left their traces in burrows and casts on the sea-floor (Arenicolites, Cruziana, Scolithus, &c.).
As respects the mode of life of the Graptolites there can be little doubt that the Dendroidea were, with some exceptions, sessile or benthonic animals, their polyparies, like those of the recent Calyptoblastea, growing upwards, their bases remaining attached to the sea floor or to foreign bodies, usually fixed.
The former term was applied to a flattened plate observed in the embryonic stage of a single genus (Antedon) at that end of the stem attached to the sea-floor, and comparable to the foot of a wine-glass (fig.
Accepting the homology of these apical systems with the calycinal system, the theory would regard the aboral pole of a sea-urchin or starfish as corresponding in everything, except its relations to the sea-floor, with the aboral pole of a fixed echinoderm.
The creature is represented crawling on the sea-floor, but it may equally well have been a floating animal.
Now ensued the great event that originated the phylum - the discovery of the sea-floor.
No other way out for them is apparent, and it is clear that Edrioaster was not permanently and solidly fixed to the sea-floor.
In the northern Apennines the elevation of the sea floor appears to have begun at an earlier period, for the Upper Cretaceous of that part of the chain consists largely of sandstones and conglomerates.
The coarser materials settle nearer the land, and the shallower portions of the sea floor are strewn with gravel and sand, except in occasional depressions and near the mouths of rivers where mud may gather.
Marine animals were present in abundance, including brachiopods which lived attached to or buried in the sea floor.
It is possible also that gas release and earthquake activity may have acted together to induce sea floor instability.
The earthquake occurred as a result of a northward thrust of the Pacific Ocean sea floor beneath the continental landmass of Alaska.
Deepening of the sea in the later Cretaceous marked the onset of the deposition of large amounts of calcareous ooze on the sea-floor.
remanent magnetization of fresh basalt lavas at the sea floor.
seafloor topography terminology, general characteristics of coastal regions, and what is on the sea floor.
The NODC holds data from the ocean water column extending from the sea surface to the sea floor.
wreckage scattered across 100,000 square feet of sea floor.
A crinoid reduced to its simplest elements consists of three principal portions - (i.) a theca or test enclosing the viscera; (ii.) five arms stretching upwards or outwards from the theca, sometimes single, sometimes branching; (iii.) a stem stretching downwards from the theca and attaching it to the sea-floor (see fig.
This is due to the strong remanent magnetization of fresh basalt lavas at the sea floor.
This lecture looks at: seafloor topography terminology, general characteristics of coastal regions, and what is on the sea floor.
Today, she lies in 30 to 55 feet of water with her wreckage scattered across 100,000 square feet of sea floor.
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