In the year 1658 the Primate of Ireland, Archbishop Ussher, declared that the creation of the Earth took place in the year 4004 B.C., a date which was repeated as a note in later editions of the Authorized Version. Thus it was deemed somewhat heretical to dispute the official age of the Earth. At the same time, super-natural forces were invoked to explain away many of the landscape’s natural forces were invoked to explain away many of the landscape’s natural features. Earthquakes were held responsible for the creation of river valleys and the Biblical Flood for the boulder clay which is so wide-spread in the northern hemisphere.
Under such influences the science of geology could make little headway and it was a Scottish geologist, James Hutton, who first perceived the real nature of the Earth’s history. James Hutton (1726 – 1797) received a scientific education which he applied to the study of geology. He attempted to trace the origin of the various rocks in order to arrive at an understanding of the history of the Earth. Another eminent geologist, Abraham Werner, held that all rocks were laid down on the floor of a primeval, universal ocean, with granites and similar rocks first, sedimentary rocks last and transitional rocks, such as shales and slates, in between. But James Hutton discovered that granite veins in Scotland had penetrated other rocks and he naturally concluded that the granite must have been not only liquid at the time but also younger than the invaded rocks. Moreover, the adjoining rocks appeared to have been ‘baked’ and changed, which suggested that the invading liquid material was also very hot.
Of even greater importance is the fact that this geological pioneer discovered the processes leading to the formation of sedimentary rocks. He saw angular fragments prised from rock faces by frost, soil being stripped from the land by streams, and rivers, laden with rock debris, discharging into the sea. He saw cliffs crumbling as storm waves pounded away at their base, and the sand of the beach being carried ut to sea by under-currents. James Hutton realised that the sediment being deposited on the floor of the sea was in fact rock in the making. He realised too that this was part of one unending cycle – land is uplifted from the sea and worn down by the tools of erosion, new rocks being formed from the debris of the old. In other words James Hutton saw that the present is the key to the past; changes that have taken place in the Earth’s crust in the past were brought about by the same causes as the changes taking place today. This philosophy came to be known as the doctrine of uniformitarianism. James Hutton’s revolutionary ideas appeared in his book The Theory of the Earth, which was published just two years before his death in 1797. But the teaching of Werner was so much in vogue that the new ideas aroused little interest at the time and it was left to later geologists to develop and champion the cause for Huttonian teaching. It ultimately prevailed over both Wernerism and the later doctrine of catastrophism which held that the modern forms of the Earth’s surface were created by a sudden overwhelming mass of water.
The history of the Earth is a continuous cycle and, as James Hutton remarked, there is ‘no vestige of a beginning and no prospect of an end’. Even today this holds true. The original rocks of the Earth’s crust must necessarily have been formed from molten material (igneous) yet the oldest igneous rocks discovered have been found intruded into even older rocks and these in turn were formed originally from the debris of other rocks. Thus a starting point to the cycle of rock change has not been found.