George Owen of Henllys, in Pembrokeshire, was a man of acute observation with a keen interest in the geological and geomorphological features of his home county. Through a section on the limestone and coal outcrops of the county in his Description of Penbrokshire (Reference OwenOwen, 1892) he gained a nineteenth-century reputation as the “patriarch of English geologists” (Anon., 1841, p. 3). Reference Conybeare and PhillipsConybeare and Phillips (1822, introduction, p. xl) believed that his geological observations represented “undoubtedly the earliest attempt to establish the important and fundamental geological fact that the same series of rocks succeed each other in a regular order throughout extensive tracts of country, and to elucidate the geological structure thus indicated”.

However, of equal importance and interest is a neglected passage in the same work (Reference OwenOwen, 1892) in which Reference OwenOwen (unpublished) set down what must be one of the most accurate early descriptions of glacial till. Referring to the till as “Claye Marle”, he wrote:

Turning his attention to the origin of the marl, Owen was prompted by all his carefully collected evidence to accept the current theory that the drift had been deposited catastrophically by the sea:

Owen noted the widespread, intermittent distribution of the till, and wrote further:

He ended his description of the clay marl with these words:

Henry Owen, who edited and commented on the description when it was re-published in 1892, noted in his preface (p. xxiv) that this “pamphlett” was completed in 1599. It may be found in the Vairdre Book of MSS. at the National Library of Wales, and contains, among other things, details of the origin and characteristics of the marl and information on where the various types of marl may be found.

Thus it seems that as early as 1599 Owen had completed his observations on the clay marl to his own satisfaction. He did not ascribe a glacial origin to the drift, but accepted, in the fashion of the day, that the marl and associated deposits had been laid down by the “great and generall flood”. Nevertheless, his work was quite outstanding for its accuracy. His description is such that one has no difficulty in recognizing his “claye marle” as the Irish Sea till which is found in both eastern Ireland and west Wales. He was correct in his observation that the till contains shell and wood fragments, and he also clearly recognized that it is everywhere characterized by a tough, compact clay matrix. He even noticed the subtle colour difference between the calcareous unweathered blue clay and the weathered and decalcified red clay which overlies it. Significantly, he recognized the till’s most important stratigraphie relationship, namely, that it is often overlain by water-deposited sands and gravels.

Reference JehuJehu (1904.), who quoted Owen’s work at length in his classic paper on the glacial deposits of north Pembrokeshire, stated that his 1599 pamphlet on the clay marl contained “perhaps the earliest attempt to give a full description of the boulder-clay”. Indeed, it may represent the earliest attempt to differentiate on a stratigraphical basis between the “Lower Till” and the “Middle Glacial Sands and Gravels” of Britain, the lower members of a tripartite glacial succession which has excited the attention of British geologists and glaciologists for so many years.