The Kellaways Formation is a geological

Geology

Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...

 formation of the Callovian Series

Callovian

In the geologic timescale, the Callovian is an age or stage in the Middle Jurassic, lasting between 164.7 ± 4.0 Ma and 161.2 ± 4.0 Ma. It is the last stage of the Middle Jurassic, following the Bathonian and preceding the Oxfordian....

 from the Jurassic

Jurassic

The Jurassic is a geologic period and system that extends from about Mya to  Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...

. It is found in the British Isles

British Isles

The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

, immediately above the Great Oolite Series

Bathonian Series

Bathonian Series refers to a series of rock strata dating from the Bathonian epoch of the Middle Jurassic.The typical Bathonian Series is the Great Oolite series of England, and the name was derived from the "Bath Oolite", extensively mined and quarried in the vicinity of that city, where the...

: below the Oxford Clay

Oxford Clay

The Oxford Clay Formation is a Jurassic marine sedimentary rock formation underlying much of southeast England, from as far west as Dorset and as far north as Yorkshire. The Oxford Clay is of middle Callovian to lower Oxfordian age and comprises 2 main facies. The lower facies comprises the...

 Formation and above the Cornbrash

Cornbrash

In geology, Cornbrash was the name applied to the uppermost member of the Bathonian stage of the Jurassic formation in England. It is an old English agricultural name applied in Wiltshire to a variety of loose rubble or brash which, in that part of the country, forms a good soil for growing corn...

. It consists of two layers, the Kellaways Sand, a light green-grey clayish silt and sand with layers of sand concretions, overlying the Kellaways Clay, a dark grey plastic fissile clay.

They were laid down during the Callovian, offshore from the London-Brabant Island

London-Brabant Island

The London-Brabant Massif or London-Brabant Platform is in the tectonic structure of Europe a structural high or massif that stretches from the Rhineland in western Germany across northern Belgium and the North Sea to the sites of East Anglia and the middle Thames in southern England.The massif...

, between 165 and 160 million years ago, in the latitude of the modern Mediterranean Sea

Mediterranean Sea

The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

, when the structure of Britain was still taking shape. At this stage, the coal swamps of the north-western shore of the island had subsided below the sea so that the Kellaways clay was formed in fairly deep water and the Kellaways sand was blown and washed from what had become the hot desert land.

For a comparable coast today, see Google Earth, coordinates 30°15'23"N 9°37'46"W. Click on the photo spot.