FAMOUS GEOLOGISTS/Agassiz 177 in primogeniture, or, what is the same thing, that they are identical species Figure Sketch in Agassiz’s Discours de Neuchaˆtel showing hypothetical fall of global temperature over time known as ‘diluvium’ (by association with the notion of catastrophic floods) or ‘drift’ (by association with the floating iceberg theory) However, the explanatory theory advanced by Agassiz was much less persuasive than that which it was supposed to explain It was widely held at the time (in accordance with the views of E´ lie de Beaumont, e.g.) that the earth was cooling Agassiz arbitrarily assumed that it did so in a fashion indicated by his sketch (Figure 2), which appeared in both the Discours and the E´ tudes This graph was supposed to represent not just a cooling inorganic planet, but one inhabited by living organisms that were wiped out, however, from time to time by ‘Cuvierian’ catastrophes, and then replaced by different sets of organisms The abrupt falls of temperature corresponded to the sudden disappearance of life forms, with the temperatures remaining approximately constant so long as the (supposedly heat sustaining) life forms continued in existence Agassiz supposed that the formation of the Alps themselves was an event of recent occurrence, was preceded by a ‘catastrophic’ fall in temperature, and was then followed by the establishment of modern forms of life On this view, then, the epoch preceding the present could have been of extreme cold, producing the former extended glaciation evidenced in the Alps The onset of cold must have been sudden, from the appearance of mammoth remains in Russia Agassiz suggested that the glaciation could have extended from the North Pole right down to the Mediterranean and Caspian seas Thus the Great Ice-Age This theory was perhaps the most ‘catastrophist’ ever propounded by a ‘respectable’ geologist (other than bolide aficionados) Agassiz wrote (1838: 382): [T]he epoch of extreme cold which preceded the present creation was attended by the disappearance of the animals of the diluvian epoch of geologists, as the mam moths of Siberia still attest, and preceded the uprising of the Alps, and the appearance of the animated nature of our day, as is proved by the moraines, and the presence of fish in our lakes There was thus a complete separ ation between the existing creation and those which have preceded it; and, if the living species sometimes resemble in our apprehension those which are hid in the bowels of the earth, it nevertheless cannot be affirmed that they have regularly descended from them Thus Agassiz set his face against transformism or evolution and offered hyper-catastrophism and the doctrine of special creations (assuming but not then stating) that they occurred by some divine means Agassiz visited Britain in 1834 and 1835, chiefly in connection with his interests in fossil fish, but he also made the acquaintance of the ‘diluvialist’ William Buckland, who in turn visited Agassiz in Switzerland in 1838 Buckland had long been interested in the drift deposits, which he earlier has ascribed to the Noachian Flood, and introduced the distinction between ‘diluvium’ and ‘alluvium’ He was, however, converted to Agassiz new theory during the course of his 1838 visit, realizing that features of British geology that had long puzzled him could be successfully explained in terms of the land-ice theory In 1840, Agassiz attended meetings of the Geological Society in London and the British Association in Glasgow, and presented his glacial theory, prompting much discussion in British geological circles However, the theory, as presented in Glasgow, tried to reconcile the new doctrine with the older idea of glacial submergence, for after the melting of the glaciers flood waters could have moved boulders and gravels (thus accounting for glaciofluvial materials) Following the meeting, Agassiz and Buckland went on a tour of Scotland, and were satisfied that they could see most satisfactory evidence in favour of the land-ice theory, and successfully interpreted the ‘Parallel Roads of Glen Roy’, which Darwin had the previous year interpreted as marine shore-lines, as being due to the successive shore lines of an icedammed lake, an interpretation that was rapidly published in the newspaper The Scotsman Following his Scottish tour, Agassiz proceeded to Ireland, where again he found ample evidence for glaciation Returning to Scotland, he then journeyed back to London, seeing many more evidences of glaciation, and spoke at the Geological Society Debates about the land-ice theory rumbled on in Britain for the next quarter century Lyell was initially converted to Agassiz’s ideas, but most other influential geologists such as Roderick Murchison (see Famous Geologists: Murchison) were not Not long after Agassiz returned to Switzerland, Lyell recanted: ‘‘he found the proposed departure from present temperature conditions too much to accept for his uniformitarianism, and he reverted to the glacial submergence theory and floating icebergs’’ It was not until the 1860s that more general acceptance of the land-ice theory began, with the suggestions of the surveyor Andrew Ramsay as to how glaciers might excavate the basins that are now