Norfolk and Norwich Naturalids' Society. 421 



I. — The Norfolk and Norwich Naturalists' Society, Norwich. 



Address by the President, Henry Woodward, LL.D,, F,E.S., 

 V.P.Z.S., F.G.S., Late Keeper of Geology, British Museum, 

 to the Members of the Norfolk and Norwich Naturalists' Society, 

 at their Thirty-fourth Annual Meeting, held at the Norwich 

 Castle Museum, March 31st, 1903.i 



After some preliminary matters relating to the affairs of the 

 Society, the President read his anniversary address, entitled "The 

 Distribution of Life in Antarctic Lands." 



Introductory — Glacial and Interglacial Periods. — During 

 the past sixty years astronomers, physicists, meteorologists, and 

 geologists have all laboured to elucidate the causes and extent 

 of the Glacial period, or, to speak more correctly — -periods. 



It seems certain that such epochs have been, in great measure, 

 brought about by a combination of astronomical causes, such as the 

 inclination of the earth's axis, the ellipticity of her orbit, and het 

 position in relation to the sun in perihelion and aphelion. But to 

 whatever combination of causes such alterations of climate in the 

 northern and southern regions of our globe may be due, we have a 

 right to demand from the astronomers and physicists the concession 

 that mild Interglacial periods of considerable duratiou must have 

 prevailed at or near the poles, certainly within Tertiary times. 

 Sir Eobert Ball says : " It is essential to the astronomical theory of 

 the Ice Age that such interglacial and glacial periods must have 

 alternated with one another at the opposite poles of our earth." 



The facts of the occurrence of extensive beds of coal and lignite, 

 associated with shale-beds rich in leaves of dicotyledonous trees 

 and shrubs in Arctic America, in North Greenland, Spitzbergen, etc., 

 within the Arctic circle ; and beds of coal with abundant tree-trunks 

 in Kerguelen Island,^ Chatham Island,^ etc., in the Antarctic, 

 where no trees now exist, testify to great changes of temperature 

 in the circumpolar regions of our earth, such as would, if they 

 recurred, render these lands again habitable by plants and animals 

 belonging to warmer temperatures, and greatly reduce, if not entirely 

 remove, all traces of snow and ice over these areas. 



Let us take a glance at the two polar regions of our earth. First : 

 let us note the fundamental difference between Arctic and Antarctic 

 conditions as regards topography. In the Northern Hemisphere 

 there is a polar sea almost completely surrounded by continental 

 land, and continental conditions for the most part prevail. In the 

 Southern Hemisphere there is almost certainly a continent at the 

 South Pole, which is completely surrounded by the ocean, and the 

 most simple and extended oceanic conditions are met with. 



^ Reprinted from the Transactions of the Norfolk and Norwich Naturalists' 

 Society, vol. vii, pt. 4, and issued to members 20th August, 1903. 



2 50° S. lat. Kerguelen Island. 



3 45° S. lat. Chatham Islands. 



