Cretaceous

The road north out of London follows an old Roman road known as Watling Street. Climbing up the side of the Thames Valley gives a view across the whole of London. In Smith's day, much of the city would have looked like a smouldering ruin covered by a pall of smoke, as thousands of household fires wafted strands of wood smoke into the atmosphere. Several decades later at the height of the Industrial Revolution, the city would have barely been visible at all as coal-burning fires belched thick...

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John Phillip's i860 diagram showing the changes in fossil diversity since Cambrian times which he used to justify his recognition of three great eras in the history of life. The duration of each era was based on measures of the total thickness of strata within each era. John Phillip's i860 diagram showing the changes in fossil diversity since Cambrian times which he used to justify his recognition of three great eras in the history of life. The duration of each era was based on measures of the...

Matching strata

With the right equipment and techniques it may be possible for our future geologist to eventually get a reasonable if not exact date match between these two mud samples. But what about the poor field geologist, someone like the pioneer English surveyor and mapmaker William Smith, tramping back and forth across the British Isles by horseback, carriage and on foot trying to match strata on a regional scale In the early days of geological mapping, the main problem was just trying to obtain any...

Miocene To Pleistocene

In the immediate Canyon area, the rock record stops in Permian times over 250 million years ago, although Earth Time has continued ever since. It is Permian-age rock strata that mostly form the present bedrock of the plateau landscape immediately surrounding the Canyon. We have climbed through about a mile's (1.6 km) thickness of Precambrian and Palaeozoic strata from the bottom of the chasm to the rim with its Permian-age strata. And although we come to an abrupt halt in our ascent through...

Pliocene To Paleocene

By the late eighteenth century and the beginning of the nineteenth century, wells were being dug deeper and deeper below London in an attempt to get a sufficient supply of clean drinking water. The population of the metropolis was fast outgrowing its water supply and the capacity of its primitive drainage system to deal with sewage. Human waste from leaking drains often contaminated the underground water table and wells sunk into it. Water-borne disease such as typhoid was on the increase....

Buffons epochs of nature

To begin with the Earth was an incandescent mass whose elements hardened into what Buflfon called a 'vitriscible' rocky state as it cooled. There was a general flood, which on retreat left fossil shells embedded in its sedimentary deposits. The large quadrupedal animals followed next and to Buffon their global distribution showed that the continents must have been joined as a single mass. The sixth epoch saw the continents separate and finally in episode seven mankind appeared. Buffon used an...

Devonian To Permian

Throughout much of the Canyon the mid and high parts of the rock walls are dominated by vertical red-stained cliffs, 150-250 m (500-800 ft) high. Powell commented as it appears along the Grand Canyon it is always stained a brilliant red, for immediately over it there are thin seams of iron, and the storms have painted these limestones with pigments from above. Altogether this is the red-wall group. It is chiefly limestone. Let it be called the red wall limestone. It subsequently became clear...

Clovis hunters and Monte Verde

The more orthodox twentieth-century answer to the question of when and how the Americas were first 'invaded' or colonised by humans was that by around 13.5 ka (i2,ooo-i4.C or radiocarbon date), migratory Siberian hunters arrived in Alaska on foot from northeast Asia. They are known as the 'Clovis' people, because of their distinctively fashioned stone spearheads that were first found in the 1930s at Clovis in New Mexico. Small bands of Clovis hunters walked across the narrow Bering Strait close...

The Precambrian rocks

'Down by the river the walls are composed of black gneiss, slates, and schists, all greatly implicated and traversed by dikes of granite. Let this formation be called the black gneiss. It is usually about 800 feet in thickness.' Powell came to dread these rocks at the bottom of the Canyon because they were tough and dangerously sharp. Rocky points and edges threatened to impale or slice open any boat or person that was thrown against them by the powerful currents of the Colorado River. And...

Paleozoic To Archean

William Smith made no attempt to deal with the oldest rocks of North Wales at the northwest end of his section. Indeed, until the latter part of the eighteenth century such mountainous terrains of the British Isles were still almost completely unknown territory and generally regarded as not only useless and inhospitable, but also uncivilised, undesirable and generally to be avoided. However, attitudes were beginning to change as artists and poets, often from urban middle-class backgrounds,...

Jurassic birds

In southern Germany, quarrying of limestone strata of similar age to England's Oolites revealed one of the most important fossil finds ever made, the oldest bird, Archaeopteryx, now known to be some 147 million years old. Originally A KCHjEOPTRRYX MAQRUBD3 (Owes). In Lb NlUonil Coll& etion, Bntiifc Khhuici. Richard Owen's drawing of Archaeopteryx shows the mixture of bird-related features such as a 'wishbone' (fu -furcula) and feathers along with a typically reptilian long bony tail....

Cambrian floods

The thickness of the sands Tapeats Sandstone, 30-100 m deposited by the ocean waters as they lapped and flooded eastwards onto the Laurentian continent was partly controlled by the residual Precambrian topography and also their relationship with the overlying muds of the Bright Angel Shale 82-137 m thick . Again, we encounter an important geological concept, that of a cross-time relationship known technically as 'diachronism' see box . The two types of strata interfinger and the time boundaries...

The Anning family

Between 1811 and 1830, the Anning family of Lyme Regis, Dorset found and recovered several strange, vaguely dolphin-like skeletons from the Liassic limestones and shales that form the local seacliffs of this part of southern England. Richard Anning 1766-1810 , the father of the family, was a carpenter and cabinet maker by trade, but was often out of work. His wife Mary, called Molly by the family, tried to supplement their precarious income by collecting and selling fossils to the growing...

Imperial ambitions and the Permian System

Roderick Murchison was 47 years old when, in 1839, he decided to make a bold career move. With the Silurian and Devonian systems reasonably well recognised and established in the British geological world see p. 193 , he wanted to see if they could also be recognised on a more international front. Perhaps they would prove to have a global significance, which really would be a 'feather in his cap'. He knew that the one relatively nearby region that had not been geologically surveyed in any detail...

Diluvial records of the Flood

Cuvier Skeleton

Occasional discoveries of very large, well-preserved bones in deposits of this kind caused a stir even as far back as mediaeval times. In 1171, the English chronicler Ralph of Coggeshall in Essex recounted how the collapse of a local river bank revealed huge bones that he thought belonged to a 'man' who 'must have been fifty feet high'. However, by the seventeenth century the idea that such bones had belonged to mythical giants had faded away, as naturalists began to recognise their true...

Ice from the Alps

The phenomenon of Alpine glaciers had fascinated naturalists for hundreds of years, but it was not until the mid-eighteenth century and the pioneering work of Scheuchzer that there was any real scientific research on them. Part of the problem was the occasional presence of huge boulders of rock called 'erratics' scattered over northern Europe and northern North America. Often they were demonstrably different in composition from the underlying rocks where they were found. What mechanism could...

Softbodied Ediacarans

As with so many apparent first discoveries in Earth Time, detailed investigation reveals some previous unsung and forgotten record that predates the generally accepted 'first' find. So it is with the strange soft-bodied and extinct Ediacaran organisms. Back in 1877, two English geologists, E. Hill and T. G. Bonney, found and described some 'curious arrangements of concentric rings which have been supposed to be organisms' on some ancient seabed surfaces in the late Precambrian sandstones of...

The nature of fossils

The discovery of fossils that looked like plant remains dates back to the seventeenth century and earlier. Collectors such as John Woodward, an English physician, amassed a diversity of crystals, minerals and organic remains, which were all then regarded as fossils since they had been dug from the ground the word 'fossil' is derived from the Latin fossa, meaning a digging or ditch . Woodward left his collection or 'cabinet' as it was then known to the University of Cambridge, along with an...