422 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



number of small stocks is so great that Mr. Brock believes that further erosion 

 would disclose a large, continuous batholith of granodiorite, of which the stocks 

 and associated dikes are roof features. (See page 387.) 



The injected igneous bodies, i.e., those which have come into place by dis- 

 placing rather than by replacing the country-rocks, include a vast number of 

 dikes, as well as a few bodies which have been described as chonoliths. It is 

 also suspected that the poorly exposed pulaskite porphyry east of Kettle river 

 bridge is chonolithic in its relations and that the dunites of this region may be 

 fairly classed with the chonoliths. 



A fuller statement as to the structural relations among the many forma- 

 tions of the western Columbia system is to be found in the foregoing des- 

 criptions of the different rocks, in the section on correlation which closes this 

 chapter, and in Mr. Brock's reports. These relations are of intrinsic interest 

 but they are also important in throwing light on the later events of the neigh- 

 bouring mountain systems where strata of Oligocene age have not been 

 discovered. 



Correlation. 



In a general way the succession of geological events which are registered in 

 the rocks of the five-mile belt between Midway and Osoyoos lake has been dis- 

 covered. A partial correlation of the formations may be made, though much 

 remains to be accomplished, especially in the analysis and proper dating of the 

 thick members which have been assembled under the name ' Anarchist series.' 

 This oldest group is almost certainly the same as that which crops out at inter- 

 vals between the Columbia river and Midway, and, in the Rossland district, 

 bears obscure fossils referred to Carboniferous species. Though the lithological 

 similarity of the Anarchist series to these Rossland rocks and, as we shall see, 

 to the very thick, fossiliferous, undoubtedly Carboniferous rocks found in the 

 Skagit range, may be an accidental and illusory resemblance, it seems best to 

 correlate the Anarchist series, or much of it at least, with the Carboniferous 

 rocks of western British Columbia. 



The dunite (serpentine) bodies of this region are intensely sheared and 

 metamorphosed and hence seem to be much older than the dunites and other 

 peridotites of the Rossland mountains. Dawson has described many masses of 

 serpentine as being nearly or quite contemporaneous with the basic effusive 

 rocks of the Carboniferous Cache Creek series of western British Columbia. In 

 the present instance it is known that the dunite cuts the phyllites of the Anar- 

 chist series and is never seen to cut the Rock Creek diorite or granodiorite; 

 further, it appears practically certain that the dunite is much older than the 

 Kettle River beds. For the present the dunite may be tentatively correlated 

 with the probably Carboniferous greenstones of the Anarchist series. The Rock 

 Creek gabbro and diorite may have direct genetic connection with the dunite, 

 though in the field their associations are with the granodiorite. 



The crushed and gneissic Osoyoos granodiorite is described in the next 

 chapter, where evidence is given for referring it to the late Jurassic period. The 

 Rock Creek granodiorite is not so much sheared but it is distinctly strained and 



