The base of the Cambrian is defined on a complex assemblage of trace fossils known as the Treptichnus pedum assemblage.

Nevertheless, the usage of Treptichnus pedum, a reference ichnofossil for the lower boundary of the Cambrian, for the stratigraphic detection of this boundary is always risky because of occurrence of very similar trace fossils belonging to the Treptichnids group well below the T. pedum in Namibia, Spain and Newfoundland, and possibly, in the western USA.

635-542 Mya ) represents the time from the end of global Marinoan glaciation to the first appearance worldwide of somewhat complicated trace fossils ( Treptichnus pedum ).

The GSSP of the upper boundary of the Ediacaran is the lower boundary of the Cambrian on the SE coast of Newfoundland approved by the International Commission on Stratigraphy as a preferred alternative to the base of the Tommotian Stage in Siberia which was selected on the basis of the ichnofossils Treptichnus pedum.

The boundary is set at the first appearance of a complex trace fossil Treptichnus pedum that is found worldwide.

Nonetheless, Treptichnus pedum is less than ideal as a marker fossil as it is not found in every Cambrian sequence, and it is not assured that it is found at the same level in every exposure.

Most geologists and paleontologists would probably set the Proterozoic-Phanerozoic boundary either at the classic point where the first trilobites and reef building animals ( archaeocyatha ) such as corals and others appear ; at the first appearance of a complex feeding burrow called Treptichnus pedum ; or at the first appearance of a group of small, generally disarticulated, armored forms termed ' the small shelly fauna '.

Trace fossils that are morphologically almost identical to the burrows ( Treptichnus pedum ) officially mark the start of the Cambrian period, suggesting that priapulids, or at least close anatomical relatives, evolved around this time.

The base of the Cambrian period is defined by the first appearance of the trace fossil Treptichnus pedum.

For instance, the presence of the fossil Treptichnus pedum was used to define the base of the Cambrian period, but it has since been found in older strata.

The stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, and probably in Spain.

The stratigraphic range of T. pedum overlaps the range of the Ediacaran fossils in Namibia, and probably in Spain.

* Epistola ad Acircium ( sive Liber de septenario, et de metris, aenigmatibus ac pedum regulis ), dedicated to King Aldfrith of Northumbria ( r. 685-704 / 5 ).

** De pedum regulis, didactive treatise on metrical feet, such as iambs and spondees.

Quo audito sacerdotes modicum subridentes et excusso pulvere pedum in eos ad alias villas festinantes in confinio Vironie tres villas baptizaverunt, ubi erat mons et silva pulcherrima, in qua dicebant indigene magnum deum Osiliensium natum, qui Tharapita vocatur, et de illo loco in Osiliam volasse.

1430 AD ), in the Vatican Library, states, over a dragon-like figure in Asia ( in the upper left quadrant of the map ), " Hic etiam homines magna cornua habentes longitudine quatuor pedum, et sunt etiam serpentes tante magnitudinis, ut unum bovem comedant integrum.

Art `` makings '' or pseudo-anthropological myths did not meet all of Patchen's requirements for a poetic frame of reference.

My memory has catalogued for easy reference and withdrawal the image of her pink, scented stationery and the unsloped, almost printed configurations of her neat, studious handwriting with which she invited me to recall our summer, so many sentences beginning with `` Remember when ; ;

This is used as a reference for comparing the ohmic heating and the electrical energy obtained from the measured current through the element and the measured voltage across the element.

With U.S. Coast Guard cooperation, the American Boat and Yacht Council was formed to develop recommended practices and standards for boats and their equipment with reference to safety.

Replies to requests for character reference are notorious for their evasive double-entendre.

The total volume of the system above the reference height is Af, and H can be eliminated to obtain an equation for the total potential energy of the system in terms of H.

Another great danger is that the emerging middle class will feel itself increasingly alienated from the political leaders who still justify their dominance by reference to the struggle for independence or the early phase of nationalism.

During the assignment pass, each instruction is examined for reference to the symbolic name of an index word or electronic switch.

When such a reference is found, an actual address is assigned and the availability table is changed so that the assigned index word or switch is no longer available for later assignment.

Publisher Richardson has updated the Blue Book `` but it still remains the compact reference book used by so many for those ever-changing telephone numbers, addresses, other residences, club affiliations and marriages ''.

The need is for reference works of a more specialized nature than individual libraries, adequate to satisfy everyday needs, could afford.

Couperin and Rameau gave titles to nearly everything they wrote, not in the later sense of `` program music '' but as a kind of nonmusical reference for the close, clear musical forms filled with keen wit and precise utterance.

But, from our reading of the Western Talmud, we Urielites believe that the Forerunner, knowing this situation would arise, made reference to and provision for divorce.

This wider definition of Anatolia has gained widespread currency outside of Turkey and has, for instance, been adopted by Encyclopedia Britannica and other encyclopedic and general reference publications.

As for the term " Compositae ", more ancient but still valid, it obviously makes reference to the fact that the family is one of the few angiosperms that have composite flowers.

A reference to the " Mad Arab " in Cthulhu Mythos fiction is invariably a synonym for Abdul Alhazred.

The history of astrometry is linked to the history of star catalogues, which gave astronomers reference points for objects in the sky so they could track their movements.

Apart from the fundamental function of providing astronomers with a reference frame to report their observations in, astrometry is also fundamental for fields like celestial mechanics, stellar dynamics and galactic astronomy.

The 1976 definition of the astronomical unit was incomplete, in particular because it does not specify the frame of reference in which time is to be measured, but proved practical for the calculation of ephemerides: a fuller definition that is consistent with general relativity was proposed, and " vigorous debate " ensued until in August 2012 the International Astronomical Union adopted the current definition of 1 astronomical unit = 149597870700 meters.

In Spanish, at least one reference reports estadounidense, estado-unidense or estadunidense are preferred to americano for U. S. nationals ; the latter tends to refer to any resident of the Americas and not necessarily from the United States.

The category of acts constituting hubris for the ancient Greeks apparently broadened from the original specific reference to mutilation of a corpse, or a humiliation of a defeated foe, or irreverent, " outrageous treatment ", in general.

In the church " the purple " is a euphemism for blood and therefore " wearing the purple " may be a reference to martyrdom or a bishop's robe.

This alphabet has influenced development of orthographies of many African languages ( serving " as the basis for the transcription " of about 60, by one count ), but not all, and discussions of harmonization of systems of transcription that led to, among other things, adoption of the African reference alphabet.

The enzyme responsible for degrading ampicillin is called beta-lactamase, in reference to the beta-lactam structure of ampicillin and related drugs.

However, the observer ( red dot ) who is standing in the rotating ( non-inertial ) frame of reference ( lower part of the picture ) sees the object as following a curved path due to the Coriolis and centrifugal forces present in this frame.

The services and protocols specified in IEEE 802 map to the lower two layers ( Data Link and Physical ) of the seven-layer OSI networking reference model.

However, reference to the latter as lochs or loughs ( lower case initial ), rather than as lakes, inlets and so on, is unusual.

The name Sabine ( Sp: Río de Sabinas ) comes from the Spanish word for cypress, in reference to the extensive growth of such trees ( here Bald cypresses ) along the lower river.

According to the reference syntax, letter-case ( upper-or lower -) is not distinguished in tag names, thus the three tags: ( i ), ( ii ), and ( iii ) are equivalent.

Developed in conjunction with the Universal Character Set standard and published in book form as The Unicode Standard, the latest version of Unicode consists of a repertoire of more than 110, 000 characters covering 100 scripts, a set of code charts for visual reference, an encoding methodology and set of standard character encodings, an enumeration of character properties such as upper and lower case, a set of reference data computer files, and a number of related items, such as character properties, rules for normalization, decomposition, collation, rendering, and bidirectional display order ( for the correct display of text containing both right-to-left scripts, such as Arabic and Hebrew, and left-to-right scripts ).

aoTuV is a modified version of the reference encoder created by a Japanese developer named Aoyumi ( aoTuV stands for Aoyumi Tuned Vorbis ), which improves its quality, especially at lower bitrates.

The first reference to the disapparance of the lower course of the Sarasvati is from the Brahmanas, texts that are composed in Vedic Sanskrit, but dating to a later date than the Veda Samhitas.

The name Yarra Valley is usually used in reference to the upper regions surrounding the Yarra River and generally does not encompass the lower regions including the city and suburban areas, where the topography flattens out, or the upper reaches which are in inaccessible bushland.

In the example depicted, the hydrometer has dropped slightly in the green liquid ; hence its density is lower than that of the reference liquid.

Sales figures as high as 35 to 40 million have been cited in various reference books and by media, as have lower numbers in the 15 – 22 million range, whilst a " more than 30 million copies " figure was quoted by Star, as early as 1983, on back cover page of Swenson's book.

Piltdown's semi-human features were made sense of by reference to non-White ethnicities who were at that time considered by many Europeans to a lower form of human.

On November 12, 2010, in a unanimous decision, the United States Court of Appeals for the First Circuit in Boston affirmed a ruling by a New Hampshire lower federal court which found that the pledge's reference to God doesn't violate students ' rights.

The term DTH predates DBS and is often used in reference to services carried by lower power satellites which required larger dishes ( 1. 7m diameter or greater ) for reception.

The term memory hierarchy is used in computer architecture when discussing performance issues in computer architectural design, algorithm predictions, and the lower level programming constructs such as involving locality of reference.

Twelve months is the lower reference limit for Time to Pregnancy ( TTP ) by the World Health Organization.

That event has since been moved to the lower tip of Manhattan and re-christened the " 4Knots Music Festival ," a reference to the speed of the East River's current.

The standard definition of a reference range for a particular measurement is defined as the prediction interval between which 95 % of values of a reference group fall into, in such a way that 2. 5 % of the time a sample value will be less than the lower limit of this interval, and 2. 5 % of the time it will be larger than the upper limit of this interval, whatever the distribution of these values.

From the frame of reference of a moving observer traveling at the speed v ( diagram at lower right ), the light pulse traces out a longer, angled path.

With reference to their studies of the ancient glass assemblages from Sepphoris of Israel, Fischer and McCray postulated that the concentration of natron, which acts as flux in glass, is slightly lower in blown vessels than those manufactured by casting.

If not else specified, it is usually the middle of the vertebral body that is used as reference, although the palpable spinous process es may be located considerably lower.