Definition of "glacial period" []

• Any period of time during which glaciers covered a large part of the earth's surface (noun)

WordNet. Princeton University. 2010.

• "Between the Miocene and the Pleistocene periods geographical changes occurred which rendered a true glacial period possible with high excentricity."
• "The distribution of life in the rivers and lakes of Brazil, the immense number of species and their local circumscription, as distinct faunae in definite areas of the same water-basin, amazed him; while the character of the soil and other geological features confirmed him in his preconceived belief that the glacial period could not have been less than cosmic in its influence."
• "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."