524 DR. J. W. GREGORY ON" THE [Nov. 1 894, 



the pole almost certainly does take place. As this, however, is period- 

 ical and of very slight amount, its effects would be insignificant. 1 



Another favourite theory — the agency of a different distribution 

 of land and water — cannot be applied in this case, unless one is 

 prepared to maintain the existence of Gondwanaland to a very late 

 Tertiary date, which probably few geologists would be prepared 

 to do. 



It seems therefore necessary to fall back on a purely local explana- 

 tion, of which the natural one is elevation, owing to which a greater 

 mass of the mountain was upreared above the snow-line. This 

 elevation may have been effected by either or all of the three follow- 

 ing agencies : — 



(1) An elevation of the whole region. 



(2) Local earth-movements of the Mount Kenya district. 



(3) By the height of the volcano before it was reduced to its 

 present level by denudation. 



In regard to the first, there seems no sufficient evidence to establish 

 the existence of any subsidence of the country for 5U00 feet. The 

 fiord-like estuaries that run up into the coastal plain, such as Port 

 Beitz, or the harbours of Kilindini, Takaaungu, or Khilifi, indicate a 

 submergence of only slight amount. The coral-reefs of the coastal 

 plain show changes of level all along the coast which vary in amount 

 from 20 to 50 feet. 



There may be evidence of a greater and older submergence in the 

 occurrence of some limestones on the Magarini Hills, though it is 

 probable that the rocks have been carried there (for some economic 

 purpose) by some exceptionally energetic native. But even if they 

 be in place, they indicate a subsidence of only some 300 feet, which 

 would be quite useless. 



It may be suggested that the depression, which formed the channel 

 of over 1000 fathoms in depth that broke the former connexion 

 between Madagascar and the mainland, indicates a subsidence of the 

 whole region of the required amount. But the differences in the 

 fauna and flora show that this was probably much older than the 

 period of maximum glaciation, while the subsidence along this line 

 is more likely to have counterbalanced a simultaneous elevation of the 



1 The principal references to the subject of the variation of latitude are as 

 follows : — 



S. C. Chandler: six papers in Astron. Journ. Nos. 248-251, 267, 277, and 

 Monthly Notices E. Astron. Soc. vol. liii. (1893) pp. 119-120. For subsequent 

 discussion, see F. Folie, ' Essai sur les Variations de Latitude,' Bull. Acad. R. 

 Sci. Brux. ser. 3, vol. xxvi. (1893) pp. 577-613 ; A. dAbbadie, ' La Fluctuation 

 des Latitudes terrestres,' Bull. Astron. vol. ix. (1892) pp. 89-102; Simon New- 

 comb, ' On the Dynamics of the Earth's Rotation with respect to the Periodic 

 Variations of Latitude,' Monthly Notices R. Astron. Soc. vol. lii. (1892) pp. 336- 

 341 ; H. G. van de S. Bakhuyzen, ' Variations of Latitude deduced from the 

 Observations of Polaris made at Greenwich 1851-89/ op. cit. vol. li. (1891) 

 pp. 286-306 ; W. G. Thackeray and H. H. Turner, ' On the Variations of Lati- 

 tude as indicated by Recent Observations at the Royal Observatorv, Greenwich,' 

 op. cit. vol. liii. (1893) pp. 2-11 ; W. G. Thackeray, 'Latitude Variation and 

 Greenwich Observations 1851-1891,' ibid. pp. 120-123, pis. iii.-v., and ibid. 

 pp. 292-296 ; G. C. Comstock, ' The Secular Variation of Latitude,' Amer. 

 Journ. Sci. uer. iii. vol. xlii. (1891) pp. 470-482. 



