500 An Outline of the Tertiary Geology of Bur'ina. 



important periods in the folding of the Himalayas. The resulting 

 structure of the anticlinorium of the Arakan Yoma and part of the 

 Tertiary synclinorium are shown in Fig. 6. The manifestation of 

 volcanic activity which has left its traces in the noble pile of Mount 

 Popa and in the interesting Crater Lakes of the Chindwin was closely 

 connected with the late Pliocene folding. It has been noted above 

 that a ridge of pre-Cambrian rocks occurs in the centre of the 

 Tertiary Belt at Shinmadaung. It may well be that this ridge 

 extended much further southwards, and even separated an eastern 

 from a western basin of deposition. This would explain the different 

 characteristics exhibited by the Pegu rocks along the eastern side 

 of the Tertiary Belt, but about which very little is yet known. 



VI. Correlation avith Europe. 



Before attempting any general correlation with European deposits, 

 it is absolutely essential to consider the geographical conditions of 

 th^ period. Many of the Tertiary deposits of Europe were laid down 

 in land-locked basins only in connexion with the main ocean (Tethys) 

 at intervals. Thus, while the sedimentation in each basin may have 

 been continuous and uninterrupted, there may be marked faunal 

 breaks due to cessation of free communication with the ocean at 

 certain periods. This is especially true of the Anglo-Franco-Belgian 

 Basin where each stage is characterized by a particular species of 

 Nummulites, but the intermediate species of Nummulites — com- 

 pleting the phylogenetic series — are only found in the main ocean. 

 It is, however, absurd to suppose — as some writers have done ^ — ■ 

 that because a certain fauna (for example, that of the " Libyan " 

 of Egypt) is not found in the Paris region, there exists a gap between 

 the Ypresian and the Lutetian, which it should occupy. One may 

 picture the geography of early Tertiary times as comprising a long 

 ocean stretching from the south of France to India, and fringed, 

 probably on either side, by partly enclosed gulfs or basins. In some 

 parts of the main ocean we may expect to find a complete series of 

 marine deposits, which should be used as a standard when comparing 

 the development of the strata in any particular basin. Amongst 

 the " fringing gulfs " may be mentioned those of the Punjab, of 

 Assam, and of Burma. Still more separated from the ocean was the 

 Anglo-Franco-Belgian Basin. Two further points must be borne 

 in mind — firstly, the probable separation of the European and Asiatic 

 portions of the Tethys in Miocene times, and secondly, that the 

 Burmese Gulf was probably far more intimately connected with the 

 Circum-Pacific Tertiary Basins than with the Tethys. ^ A rough 

 correlation of the Burmese and North- Western European Tertiaries 

 is appended in tabular form. 



1 Rec. G.S.I., vol. li, pt. iii, 1921, pp. 325-6. 



^ Vaughan and others, " Correlations of the Post-Cretaceous Formations in 

 the Pacific Region." Reprinted from special publication of Bernice P. Bishop 

 Museum, No. 7, 1921, pp. 713-873. 



