Elizabeth Cary Agassiz, Louis Agassiz: his life and correspondence, third edition

[263] various works on fishes, radiates, and mollusks, a new chapter of nature was all the while unfolding itself in his fertile brain. When the Helvetic Association assembled at Neuchatel in the following summer, the young president, from whom the members had expected to hear new tidings of fossil fishes, startled them by the presentation of a glacial theory, in which the local erratic phenomena of the Swiss valleys assumed a cosmic significance. It is worthy of remark here that the first large outlines in which Agassiz, when a young man, planned his intellectual work gave the key-note to all that followed. As the generalizations on which all his future zoological researches were based, are sketched in the Preface to his ‘Poissons Fossiles,’ so his opening address to the Helvetic Society in 1837 unfolds the glacial period as a whole, much as he saw it at the close of his life, after he had studied the phenomena on three continents. In this address he announced his conviction that a great ice-period, due to a temporary oscillation of the temperature of the globe, had covered the surface of the earth with a sheet of ice, extending at least from the north pole to Central Europe and Asia. ‘Siberian winter,’ he says, ‘established itself ’