8 M. Ami Botie on the Palccohydrography 



geognostical way I have shewn the place that the sea has 

 occupied in older periods. During the Alluvial time a good 

 deal of land formed by Tertiary beds, Chalk, Jura beds, and 

 even by Primary fossiliferous and crystalline rocks, subsided 

 in the Atlantic, and in the Pacific the countries that disap- 

 peared may have belonged to the tertiary, primary, and crys- 

 talline rocks. To the south-east of Africa, fragments of 

 land have subsided, belonging to all the four classes of for- 

 mations. 



In the middle and older secondary periods, it would seem 

 that the countries lying on equatorial lines in the Pacific did 

 replace the Australian countries, which had again subsided, 

 as well as part of the dry land of both peninsulas in Hindu- 

 stan. The secondary formations do not appear in these latter 

 countries, because they could not be formed there. Accord- 

 ing to similar considerations, it may appear probable that a 

 part at least of Eastern America and a part of Western 

 Africa were again put under water by subsidences. It is 

 possible that the rent of the Red Sea took its origin in that 

 time, for it is surrounded by much chalk and tertiary rocks. 

 Later, at the end of the Jura time, on the contrary, these 

 countries must have been thrown up, and the motion must 

 have lasted till the Alluvial time. This we prove by the 

 chalk mountains, and the now dry tertiary basins. 



In the Primary period were islands in all seas, especially 

 distributed in an equatorial direction, because this position 

 coincides most with the density of the centrifugal force, 

 which had not then attained its present limits in the process 

 of rotation. 



Before we conclude, we may observe that later observa- 

 tions will certainly complete this essay. Through the pro- 

 gress of palaeontology, and natural history, zoologists and 

 botanists have been able not only to restore and delineate to 

 us the old fauna and flora, but they have also deciphered the 

 philosophical plan of the origin and development of organic 

 nature. In the same way, geology and physical geography 

 will illustrate the once palseohydrography and orography, and 

 follow nearly all the changes in the palatoplasties of the 

 earth. We shall obtain then, as complement of our actual 



