ON THE MOVEMENTS OF THE EARTH ,S CRUST. 



375 



Marne et Molassc Marine, beds 221 to 231. Clay alternatii)g' with 

 marly limestone and sandstone three or four times. The npper part of 

 arc 7'. 



Sables de Fonfenai/e, bed 2.32. Marine sand with a few layers of clay, 

 but without marked alternations. The latter part of arc 7'. 



Calcaire de Beance (p. p.) Fresh water, between arcs 7' and S' 



From this we get a complete agreement with the paheontological re- 

 snlts, as shown by the following comi)arison of the equivalent forma- 

 tions in both basins : 



It will be seen that the number of alterations of strata is about the 

 same in the synchronous formations in the Paris and Hampshire Basins. 

 This shows that this alternation of strata was due to a general cause; 

 and that this cause is the precession of the equinoxes, seems highly 

 probable. 



As moreover the curve of the eccentricity of the earth's orbit ap- 

 pears at the same time to be a curve of the variations of the sea-level, 

 we may also conclude with probability that for one reason or another 

 the sea rose and fell with the eccentricity. 



