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
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...