As the Internet developed, arguments about 0.999... are often on newsgroups and message boards. Even newsgroups and message boards that do not have much to do with math argue about this. In the newsgroup sci.math, arguing about 0.999... is a "popular sport". It is also one of the questions in its FAQ.
Ophthalmosauridae
Ophthalmosauridae were a family of Ichthyosaurs which lived from the Middle Jurassic to the Upper Cretaceous period.
Within Ophthalmosauridae there are two lineages, one including "Aegirosaurus" and "Ophthalmosaurus", and the other including "Brachypterygius", "Caypullisaurus" and "Platypterygius".
Only three genera survived the end-Jurassic extinction event: "Caypullisaurus", "Maiaspondylus", and "Platypterygius". They did, however, have a worldwide distribution. The last to survive was "Platypterygius". This genus became extinct about 30 million years before the end of the Upper Cretaceous period. It happened when there was a deep ocean anoxic event, which wiped out all the animals below pelagic waters. Ichthyosaurs, being reptiles, came to the surface to breath, but the extinction event removed their prey species.
Anoxic event
An anoxic event (AE) is an event in which parts of the ocean have become low in oxygen (O) below the surface levels, or when all the oxygen has gone. They may be called oceanic anoxic events or deep ocean anoxic events.
Major anoxic events have happened, though not for millions of years. The geological record of organic-rich sediment (black shales) shows that they happened in the past. However, only "in rare, extreme cases, [did] euxinia lead to biotic crises. [The] hypothesis [is] best supported by evidence from the end-Permian mass extinction".
Anoxic events may have caused mass extinctions. These mass extinctions were so characteristic that they have been used by geologists as markers in biostratigraphic dating. Typically, oceanic anoxic events last for under half a million years, before a full recovery.
There are several places on earth today that show the features of anoxic events on a localized level. 'Dead zones' exist off the East Coast of the United States in the Chesapeake Bay, in the Scandinavian strait Kattegat, the Black Sea, in the northern Adriatic and off the coast of Louisiana.
It is not known why anoxic events may have happened. Some ideas include:
All of these events may have caused mass extinction in the seas, changing ways in which all animals which feed on sea creatures.
Metriacanthosaurus
Metriacanthosaurus is a genus of theropod dinosaur that lived in Europe during the Middle Jurassic period, about 160 million years ago. Its name means "Moderate-spined lizard", because its back vertebrae are taller than other meat-eating dinosaurs such as "Allosaurus", but shorter than those of other meat-eating dinosaurs, such as "Acrocanthosaurus". Like most theropods, "Metriacanthosaurus" was a meat-eater. It had three fingers on each hand. Each finger ended in a sharp, hook-like claw that was used to grab prey before giving the killing bite with its jaws. It probably preyed on the large, long-necked sauropods, such as "Pelorosaurus", that lived in the same time and place as it. It was originally classified as a megalosaurid, but recent studies show that it belongs to its own family, the Metriacanthosauridae
In "Jurassic Park", one of the vials of dinosaur DNA that Dennis Nedry steals is labeled "Metriacanthosaurus".
Acrocanthosaurus
Acrocanthosaurus was a genus of theropod dinosaur that lived in North America during the Lower Cretaceous period. Its name means "high-spined lizard". This refers to the spines on its vertebrae which formed a sail or hump when the animal was alive.
Its classification is uncertain. It was originally classified as a spinosaur, because the spines on its back looked like those of "Spinosaurus". However, "Acrocanthosaurus" is now classified as a carnosaur. Most paleontologists believe that it was a carcharodontosaurid.
"Acrocanthosaurus" was 39 feet long, almost as large as "Tyrannosaurus rex", and weighed about 6 or 7 short tons. It was the largest theropod in North America before the evolution of the tyrannosaurs.
Long, low ridges start at the nasal bones. They run along each side of the snout from the nostril back to the eye, and they continued onto the lacrimal bones. This is a characteristic feature of all allosaurids.
There is a famous trackway in Paluxy, Texas, which shows tracks of what might be an "Acrocanthosaurus" and its prey. While interesting and plausible, this hypothesis is difficult to prove and there are other explanations.
"Acrocanthosaurus" was featured in an episode of the television documentary "Monsters Resurrected". It was depicted as the top predator in early Cretaceous North America. A juvenile was scared away from its kill by a pack of "Deinonychus", and was forced to hunt more difficult prey, such as a "Sauropelta".
Flood basalt
A flood basalt or trap basalt is the result of a giant volcanic eruption or series of eruptions that coats large stretches of land or the ocean floor with basalt lava.
Flood basalts have covered areas as large as a continent in prehistory, creating great plateaus and mountain ranges. Flood basalts have erupted at various times throughout Earth history. They are clear evidence that the Earth has periods of higher activity rather than being in a uniform steady state.
One explanation for flood basalts is that they are caused by the combination of continental rifting and its associated melting. Then a mantle plume produces vast quantities of a basaltic magma. These have a low viscosity, which is why they 'flood' rather than form taller volcanoes.
Flood basalts start at between 100 and 400 km depth, in the asthenosphere. To get a partial melting as large as that of the traps, expelling huge quantities of lava, it is necessary to have a large heat input. Such melting can take place near a hotspot, resulting in a mixture of magma from the depths of the hotspot with superficial magma produced by a mantle plume.
A lava plateau is a flat, wide surface (plateau) that is formed when lava comes out of the ground and spreads out very quickly. The layers of lava can build up over time to form a lava plateau. Here are the general properties of lava plateaux:
The Emeishan Traps in southwestern China, around Sichuan province, the Deccan Traps of central India, the Siberian Traps, and the Columbia River Plateau of western North America are four large regions covered by prehistoric flood basalts. The two largest flood basalt events in historic time have been at Eldgjá and Lakagigar, both in Iceland. The largest and best-preserved continental flood basalt terrain on Earth is part of the Mackenzie Large Igneous Province in Canada. The maria on the Moon are additional, even more extensive, flood basalts. Flood basalts on the ocean floor produce oceanic plateaus.
The surface covered by one eruption can vary from around 200,000 km² (Karoo) to 1,500,000 km² (Siberian Traps). The thickness can vary from 2000 metres (Deccan Traps) to 12,000 m (Lake Superior). These are smaller than the original volumes due to erosion.
Another example of a lava plateau is the Giant's Causeway, in County Antrim, Northern Ireland. This is was originally part of a great volcanic plateau called the Thulean Plateau.
Monterrey
Monterrey is a city in northern Mexico. It is the capital of the state Nuevo León. It is the third largest city in Mexico. It has 2,056,538 people.
Siberian Traps
The Siberian Traps form a large region of volcanic rock, known as a large igneous province, in the Russian region of Siberia.