Prof. Bonney — Sodalite Syenite from the Rochy Mountains. 199 



not only iu its canines and incisors, but in its molars as well; they 

 are of an even more generalized character and closely approach to 

 those of the Casino form, though being of still smaller size. 



In my opinion, therefore, this Pleistocene insular form is a slightly 

 modified survivor of Tertiary Hippopotamidas, as is also the recent 

 S. Liber iensis — the latter, by the way, a parallel to that other early 

 type, the Ocapia ; the former points out the road, or one of the 

 roads, by which the Hippopotami may have passed from Africa 

 to more northern regions, before Cyprus was severed from its 

 connection with the neighbouring continents. There are therefore 

 good reasons for supposing that the Oligocene and Miocene ancestors 

 of the Hippopotami had their home in Africa. 



The assumption of a, geologically speaking, recent appearance 

 of the Hippopotami in Madagascar is based on the more modernized 

 characters of the Malagasy Sippopotami, as compared with the 

 Pliocene members, with H. minutus and with H. Liberiensis, which 

 characters place the first-named nearer to H amphibius. 



II. — On a Sodalite Syenite (Ditroite) from Ice Kiver Valley, 

 Canadian Eocky Mountains. 



By Professor T. G. Bonney, D.Sc, LL.D., F.R.S. 



IN the year 1886 the late Dr. G. M. Dawson gave an account' 

 of a syenitic rock, rich in a beautiful blue sodalite, which he 

 had discovered when exploring the district near Hector Pass, ou 

 the watershed of the Canadian Rocky Mountains, and an analysis 

 of the mineral was afterwards published by Professor Harrington.^ 

 The place was visited last Summer by Mr. E. Whymper during his 

 examination of the district south of the Canada Pa,cific Railway, 

 when he collected a number of specimens, which he showed to me 

 on his return. The rock is hardly less beautiful than lapis lazuli, 

 and as no description of its microscopic structure has been published, 

 as far as I can ascertain, I give the results of my examination, 

 together with a condensed account of its mode of occurrence. I am 

 much indebted to Mr. Whymper for placing his specimens at my 

 disposal, to Mr. L. Fletcher, Keeper of the Mineral Collection in 

 the British Museum, for the opportunity of examining specimens of 

 sodalite rock not in my own cabinet, and to Mr. L. J. Spencer, 

 of that department, for giving me his kind assistance and valuable 

 references to papers about the mineral. 



Dr. Dawson states that the Beaver-foot Range, on approaching 

 the Kicking Horse River,^ becomes bordered by rounded and wooded 

 hills, composed of slaty Cambrian rock, which, so far as can be 



1 ' ' Physical and Geological Features of that portion of the Eocky Mountains 

 between lat. 49° and 51° 30'" : Geol. and Nat. Hist. Survey of Canada, 1885, 

 p. 122, B. 



^ Trans. Eoy. Soc. Canada, vol. iv, sect, iii, p. 81. 



^ Hector Pass, by which the Canada Pacific Railway crosses the watershed of the 

 continent, was formerly called Kicking Horse Pass. 



