ON THE MOVEMENTS OF THE EARTh's CRUST. 361 



We have already seen that the hxiul (according to Iloworth and Sness) 

 in many places under high latitudes rose considerably in the Postglacial 

 period, and that a corresponding depression took place in the warm coral- 

 seas. The last oscillations therefore affected a great i)art of the earth. 

 From this we may conclude that this was the case also with the oscilla- 

 tions of former times, and that they have their cause in general cosmi- 

 cal conditions. The small oscillation (arc 4") forms an interruption in 

 this great upheaval under high latitudes. A similar interruption of the 

 depression, if our theory be correct, must be exhibited under the trop- 

 ics ; and in reality in the equatorial parts both of America and the Old 

 World, there are numerous evidences of such a small post-glacial oscil- 

 lation in coral-reefs, which have been upraised several meters and are 

 now lying dry (see Suess, AnUitz der Urde, ii, \)\\ CiO et seq). These 

 coral-reefs may date from the same time when tlie northern peat-beds 

 were submerged. The sunken peat-beds with the marine deposits 

 formed during the depression have been again uplifted, and the raised 

 coral-banks have probably again begun to sink (at Bombay there is a 

 sunken forest), but the depression has not yet brought them down be- 

 neath the sea. 



We may make one or two further observations upon the Glacial 

 period and its formations. Contemporaneous with "the forest-bed of 

 Cromer" (according to Heer) are the lignites of Diirnten in Switzerland. 

 The fossils show this. They have nearly the same plant-remains, and 

 the same extinct animals. The lignites rest upon and are covered by 

 bottom-moraines, and are therefore "inter glacial." They have seven 

 alternations of peat and forest-beds, and may be fitted into the curve 

 between the arcs 15' and 1". From this the Alps must have had large 

 glaciers even during the time of the Red Crag. And there is no im- 

 probability in this if we remember that Leda arctka and other Arctic 

 animals were already living on the English coast at this period, and that 

 the Chillesford beds indicate a much colder climate than the subsequent 

 forest- bed of Cromer. 



It is instructive to see how each rising of the sea in England during 

 the Quaternary period had as its consequence the increase of the inland 

 ice. This seems to agree with Croll's theory, that glacial periods are a 

 consequence of great eccentricities. But the scanty traces of glacial 

 periods in the older formations, and aboveall thedistribution of glaciers 

 at the present day, show that geographical conditions have the greatest 

 influence. It is only when these are favorable that a high eccentricity 

 can cause the glaciers to increase; if they are very favorable, there 

 may be a glacial period even during a small eccentricity, as in Green- 

 land at tlie present day. When the eccentricity increases, the precipi- 

 tation during rainy periods also increases. If the sea is cold, the pre- 

 cipitation will fall as snow, and in this way the glaciers will grow as 

 the eccentricity increases. 



North Germany (according to Jentzsch) has also had three glacial 



