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The Continental Shelf is the area of a shallow seabed around a large landmass.

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This Reptile's fossils were found in BOTH South America and Africa proving that they were connected at some point.

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Mesosaurus (Greek for "middle lizard"); pronounced MAY-so-SORE-us

Swamps of Africa and South America

Early Permian (300 million years ago)

About three feet long and 10-20 pounds

Plankton and small marine organisms
Distinguishing Characteristics:
Slender, crocodile-like body; long tail

Mesosaurus was the odd duck (if you'll excuse the mixed species metaphor) among its fellow prehistoric reptiles of the early Permian period. For one thing, this slender creature was an anapsid reptile, meaning it did not have any characteristic openings on the sides of its skull, rather than a more common synapsid (a category that embraced the pelycosaurs, archosaurs and therapsids that preceded the dinosaurs; today, the only living anapsids are turtles and tortoises). And for another, Mesosaurus was one of the first reptiles to return to a partially aquatic lifestyle from its fully terrestrial forebears, like the prehistoric amphibians that preceded it by tens of millions of years. Anatomically, though, Mesosaurus was pretty much plain vanilla, looking a bit like a small, prehistoric crocodile - that is, if you're willing the overlook the thin teeth in its jaws that seem to have been used to filter plankton.

Now that all that's been said, however, the most important thing about Mesosaurus is where it lived. The fossils of this prehistoric reptile have been discovered in eastern South America and southern Africa, and since Mesosaurus lived in freshwater lakes and rivers, it clearly couldn't have swam across the expanse of the southern Atlantic Ocean. For this reason, the existence of Mesosaurus helps support the theory of continental drift - that is, the now-well-attested fact that South America and Africa were joined together into the giant continent Gondwana 300 million years ago before the continental plates supporting them broke apart and drifted into their current positions. (By the way, Mesosaurus shouldn't be confused with Mosasaurus, another, much bigger, and much scarier marine reptile that lived 200 million years later!)

Mesosaurus is important for yet another reason: this is the earliest identified animal to have left amniote embryos in the fossil record (the eggs of amniote animals are either laid on land or incubate in the mother's womb, as distinguished from the eggs of fish and amphibians, which are laid in the water). It's widely believed that amniote animals existed a few million years before Mesosaurus, only recently evolved from the first tetrapods to climb up onto dry land, but we have yet to discern any conclusive fossil evidence for these very early amniote embryos.

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Meet the Fascinating Mesosaurus, an Odd Prehistoric Reptile

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Get an in-depth profile of Mesosaurus, including this marine reptile's characteristics, behavior, and habitat.

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This Trassic Tree was found in India, South America, Australia, Africa, and Antarctica

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The Glossopteridales are an extinct group of seed plants that arose during the Permian on the great southern continent of Gondwana. These plants went on to become a dominant part of the southern flora through the rest of the Permian, though they dwindled to extinction by the end of the Triassic Period.

Glossopteris, the genus from which the group gets its name, is also the largest and best-known member of the Glossopteridales. More than 70 species of this genus have been recognized in India alone, with additional species from South America, Australia, Africa, and Antarctica. Only a few fossils from the northern hemisphere have been considered as members of this group, but these are not identified with great certainty.

The rapid appearance, expansion, and relatively quick extinction of this group, as well as the large number of species, has made the group very important for understanding paleobiogeography, specifically in the recognition of areas that were once connected together, but are now separated through the action of continental drift. As a result, there is a wealth of descriptive literature available on glossopterids. However, most of the available fossils are sterile leaves lying unattached to stems, and so a number of species which have been described are not well differentiated, and few are known from distinctive reproductive structures. This makes it difficult to be certain of the actual number of species.

The large number of leaves found preserved, and the character of the deposits in which these are found, suggest that glossopterids were deciduous, losing their leaves in the autumn, and growing new leaves in each spring. Some specimens show an abscission zone, such as that along which a leaf detaches in living plants. A number of tiny scale-leaves have also been found; these may represent first-growth leaves or bud scales. Mature leaves were often 10 cm long, and some leaves have been found over a meter in length. These mature leaves are very easy to recognize, since they have a strong central vein and a network of smaller veins. This is quite different from the other seed plants of the Late Paleozoic and early Mesozoic, which usually had no midvein and secondary veins which ran parallel to each other. You can see the striking preservation of these vein networks in the picture below.

The pictures above show features of Glossopteris leaves. The image on the left shows the fine preservation of leaf veins, while the one on the right shows smaller leaves which may be first-growth leaves or bud scales. The leaf on the left was collected in Antarctica, and those on the right from South Africa. Click on either image to view an enlargement.

The reproductive structures of glossopterids are as unusual as the foliage leaves. They appear to have been borne on leaves as in other " pteridosperms". Poor preservation has led to much controversy over their structure and their arrangement on living plants from which they came. At least one point has become clear: pollen and seeds were produced in different organs, attached to separate leaves, though the specifics of the organs themselves are not as clearly settled. Pollen organs have been described as anything from a modified leaf bearing stalked pollen sacs to cone-like clusters.

More common as fossils than pollen organs are ovule-bearing organs (those that are responsible for producing seeds). A dazzling variety of these structures has been found, suggesting that this really was a large and diverse group of plants. Seeds appear to have been produced on the underside of the leaf, with the leaf edges rolled over to form an enclosing chamber. This may not have been the case for all species, since at least some fossils have been reconstructed with ovules hanging in clusters from a much smaller, and un-enclosing leaf.

In addition to their distinctive foliage and reproductive structures, glossopterids also have unusual roots. These have been asigned to the form genus Vertebraria, so called because of the regularly spaced partitions which give the appearance of a backbone. The roots are remarkable for the lobed wood at their center, with internal spaces between the lobes -- a highly unusual morphology among plants.

Vertebraria: The roots of glossopterids have regular cross-partitions that give them the appearance of a vertebrate backbone. This specimen was found in Permian deposits from India. Click on the above image for a more detailed view.

The most frustrating aspect of glossopterid paleobiology is that no one is really certain what these plants looked like. Large portions of plants have never been preserved intact, and so reconstructing them has been done from rather tiny pieces. Our best guess is that they were large shrubs or small trees, perhaps a bit like a magnolia or ginkgo. There is at least some evidence that, like Ginkgo, glossopterids had a stem system of both long and short shoots. In Ginkgo, it is the short shoots that produce most of the leaves, and that bear the seeds and pollen structures. This may also have been the case for the glossopterids, but no one is certain.

Source:
Taylor, T. N. & E. L. Taylor. 1993. The Biology and Evolution of Fossil Plants, Prentice Hall, NJ, USA.

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The Glossopteridales are an extinct group of seed plants that arose during the Permian on the great southern continent of Gondwana. These plants went on to become a dominant part of the southern flora through the rest of the Permian, though they dwindled to extinction by the end of the Triassic Period.

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Both of these species' fossils were found on different continents proving that they might have been connected at some point

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This data mostly consists of Tree rings, Coral, and lake sediments.

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Paleoclimatology data are derived from natural sources such as tree rings, ice cores, corals, and ocean and lake sediments. These proxy climate data extend the archive of weather and climate information hundreds to millions of years. The data include geophysical or biological measurement time series and some reconstructed climate variables such as temperature and precipitation.

NCEI provides the paleoclimatology data and information scientists need to understand natural climate variability and future climate change. We also operate the World Data Service for Paleoclimatology, which archives and distributes data contributed by scientists around the world.

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Paleoclimatology data are derived from natural sources such as tree rings, ice cores, corals, and ocean and lake sediments. These proxy climate data extend the archive of weather and climate information hundreds to millions of years. The data include geophysical or biological measurement time series and some reconstructed climate variables such as temperature and precipitation.

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Paleoclimatic data is mostly found from this age in Greenland and Antartica

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The only way for tropical Fossils to end up in colder climates is a large shift in climate and movement of the tectonic plates.

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This is a study of how earth used magnitism to form and its magnetic feild at the time it formed.

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The record of the strength and direction of Earth's magnetic field (paleomagnetism, or fossil magnetism) is an important source of our knowledge about the Earth's evolution throughout the entire geological history. This record is preserved by many rocks from the time of their formation. The paleomagnetic data have played an instrumental role in deciphering the history of our planet including a decisive evidence for continental drift and global plate tectonics. The data have also been crucial for better understanding the problems of regional and local tectonics, geodynamics, and thermal history of our planet.

The paleomagnetism of rocks of the ~1.1 billion year old North American Midcontinent Rift have been intensively studied since early 1960s (for example, see a review in Halls and Pesonen, 1982). The rifting began during an interval of reversed polarity of geomagnetic field. The reversely magnetized lavas (the Siemens Creek formation of Powder Mill group, the lowermost part of North Shore volcanics, Osler volcanics, and the lower part of Mamainse Point formation) are found in many locations around Lake Superior (see figure from , below).

This early stage magmatism occurred from 1108 to approximately 1105 million years ago. The period of active magmatism was followed by a quiescence period when a geomagnetic field reversal took place.

Magmatism renewed by 1102 Ma () during the normal polarity interval. During this interval, a sequence of Portage Lake lava flows erupted within a two to three million year interval around 1095 million years ago. These rocks represent the main stage of the rift-related magmatism. All younger sedimentary and igneous suites exposed on the Keweenaw peninsula (the Copper Harbor conglomerate, LST, etc) have normal polarity magnetization.

However, the geomagnetic field reversal mentioned above is characterized by an asymmetry, manifested in natural magnetization recorded by Keweenawan rocks that crop out around the Lake Superior (e.g., Palmer, 1970; Halls and Pesonen, 1982; Pesonen and Halls, 1983; Schmidt and Williams, 2003). Most but not all of the reversely magnetized ("reversed") lava flows and dikes of this age consistently have characteristic directions of magnetization that are about 20 to 40 degrees steeper in inclination than their normally magnetized ("normal") equivalents, while declinations show the expected 180 degree relationship. The paleomagnetic pole positions derived from these normally and reversely magnetized rocks define a noticeable amount of apparent polar wander that forms the western arm of the so called "Logan Loop" ( Robertson & Fahrig, 1971) (see figure from Robertson & Fahrig, below).

The two most favored hypotheses for this reversal asymmetry are either apparent polar wander during Keweenawan times (Davis and Green, 1997; Schmidt and Williams, 2003) or the presence of a persistent non-dipole field causing the geomagnetic field to depart from a geocentric axial dipole geometry (Pesonen and Nevanlinna, 1981; Halls and Pesonen, 1982; Nevanlinna and Pesonen, 1983; Pesonen and Halls, 1983). The recent study of this problem () on lavas from Mamainse Point shows that the geomagnetic reversal asymmetry observed in rocks of Keweenawan age is an artifact of the rapid motion of North America during this time. The other study by Kern et al, (2012) on rocks of the alkaline Coldwell Complex (Ontario, Canada) also suggests no asymmetry in geomagnetic reversal during Keweenawan time.

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The record of the strength and direction of Earth's magnetic field (paleomagnetism, or fossil magnetism) is an important source of our knowledge about the Earth's evolution throughout the entire geological history. This record is preserved by many rocks from the time of their formation.

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In order to track Earth's magnetic poles trough time you can use magnetic rock found in volcanos. This shows that the continents have moved if the magnetic poles have changed then the continents must have drifed aswell.

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Every magnet produces an invisible area of influence around itself. When things made of metal or other magnets come close to this region of space, they feel a pull or a push from the magnet. Scientists call these invisible influences FIELDS.

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What is the evidence for continental drift?

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What is the evidence for continental drift?

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Alfred Wegener theorized that there was a super continent, and that the continents drifted apart. The examples that he used to theorize are the same rock layers in the Appalachian Mountains in the US and in Scotland. Fossils found in eastern Brazil matched with those in South Africa. http://scienceline.ucsb.edu/getkey.php?key=2842

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They use Paleoclimatic data such as tree rings, ice cores, and coral.

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Scientists study Earth's climate and the ways that it changes in a variety of different ways, using satellite, instrumental, historical, and environmental records. One challenge of using satellite and instrumental data is that their lifespans have been rather short when compared to Earth's life. The satellite record is only a little over 20 years old and the instrumental record only extends back into the 19th century. Both of these records can be too short to study certain climate processes that occur over hundreds to thousands of years.

To extend those records, paleoclimatologists look for clues in Earth's natural environmental records. Clues about the past climate are buried in sediments at the bottom of the oceans, locked away in coral reefs, frozen in glaciers and ice caps, and preserved in the rings of trees. Each of these natural recorders provides scientists with information about temperature, precipitation, and more. Many of these have some type of layers, bands, or rings that represent a fixed amount of time, often a year or growing season. The layers vary in thickness, color, chemical composition, and more, which allows scientists to extrapolate information about the climate at the time each layer formed.

Scientists can then take the records left by many different types of natural records and combine them to get an overall picture of the global climate. Typically, records that have large timespans have less detail about short-term climate changes, while shorter records are often more detailed. To combine them, scientists must use records with similar levels of temporal detail or account for these disparities to accurately paint a picture of ancient climates.

Visit the Paleoclimatology Data page to learn more about and access all of the historical data NCDC's Paleoclimatology Program stewards. Or visit What is Paleoclimatology? to learn more about the study of ancient climates.

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How Do Scientists Study Ancient Climates?

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Scientists study Earth's climate and the ways that it changes in a variety of different ways, using satellite, instrumental, historical, and environmental records. One challenge of using satellite and instrumental data is that their lifespans have been rather short when compared to Earth's life.

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Varves are layers of clay and silt at the bottom of a lake that show years accoording to their color.

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Varves are seasonal sediment alternations which appear to represent annual cycles. They are widely studied and correlated, because seasons cause sedimentary variations that repeat. Like tree rings, they allow us to see year by year change, they record climate and lake level change events and allow reconstruction of evolving landscapes. We are very rich in varved deposits, and can visit them readily in many nearby places where fine sands silts and clays are exposed such as at Coles Creek near Houghton on the Houghton Canal Road.

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Varves are seasonal sediment alternations which appear to represent annual cycles. They are widely studied and correlated, because seasons cause sedimentary variations that repeat. Like tree rings, they allow us to see year by year change, they record climate and lake level change events and allow reconstruction of evolving landscapes.

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Glacier marks, paths of dug up rock and silt.

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Illinois State Geological Survey Tillites | ISGS

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Tillite is the name for the type of glacial erratic shown in this photo (below). Fairly common in the glacial drift of Illinois, these tillites were derived from Canadian Shield rocks (Precambrian Gowganda Formation) of Ontario. Tillite (also called diamictite and mixtite) is made up of sediment that was carried or deposited by a glacier and later cemented to form rock.

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Glacial Striations are scratches in the earth caused by a powerful glacier that has gone by. this proves the continential drift theory because austrailia, antartica, lower africa, south america and india all have simmilar glacier marks showing that there might have been a large ice sheet accross pangea.

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One of the most important contributions to the development of plate tectonic theory was Alfred Wegener's 1915 publication of 'The origin of continents and oceans' which outlined his theory of Continental Drift. Wegener supported his argument with five lines of evidence.

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What did scientists in the 1960s discover about Continental Shelfs?

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What did scientists in the 1960s discover about Continental Shelfs?

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In the 1960s, scientists like Harry Hammond Hess discovered that oceans like the Atlantic expanded the sea floor from their mid-ocean ridges, spreading both the continents and sea floor. https://futurism.com/continental-drift-theory-2

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Which Mt. ranges might have been together at one point?

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Which Mt. ranges might have been together at one point?

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A couple of mountains that might have been together were the Rockies Mountains in North America and the Andes in South America. There also might have been the Appalachian Mountains and the Scottish Highlands.

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Scientists might have known that some mountain ranges were together at one point because of similar age and type of rocks found in two different ranges.

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What would a map look like with all the continents together?

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What would a map look like with all the continents together?

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The map would look like this, or Pangea.

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Why is this good evidence for Continental Drift?

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Why is this good evidence for Continental Drift?

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All this information about similar rocks in different parts of the world is good evidence for Continental Drift because the rocks, based off their age, most likely have been part of the same mountain range millions of years ago, that eventually split apart.