520 DEPARTMENT OF THE INTERIOR 



2 GEORGE V., A. 1912 



In 1901 a brief examination of these beds was made. The exposures are gener- 

 ally small and poor, so that a complete treatment of the series cannot be given. 

 It consists of heavy masses of medium-grained, gray-tinted conglomerate alter- 

 nating with sandstone and shale, the conglomerate being apparently most 

 abundant at the base of the group. Unlike the clastic rocks of the Tamihy 

 series, these are friable to a notable extent. Thin and seemingly unworkable 

 beds of tolerable coal have been found in the upper part of the formation, and it 

 is reported that borings have declared the presence of a valuable bed of fire-clay 

 which was found beneath the ledges cropping out at the edge of the Eraser river 

 alluvium southeast of the main sedimentary area. 



The conglomerates contain pebbles manifestly derived from the (Chilliwack 

 series ?) quartzite and from the Sumas granite, with both of wnich the sedi- 

 ments make unconformable contact. The sandstones are feldspathic and arkose- 

 like. The shales are sometimes carbonaceous, and at a point about 800 feet 

 above the prairie and near the northern edge of the formation as mapped, Messrs. 

 D. G. Gray and M. McArdle, who were in charge of the boring operations, dis- 

 covered some fossil leaves in the shales. 



The fossils were found in the vicinity of a thin coal-bed which is consider- 

 ably broken, and seems not to afford a body large enough for economical working. 

 The plant specimens were submitted to Mr. F. H. Knowlton, who reported that 

 the collection was of little diagnostic value. He writes that the material has 

 somewhat the appearance of species regularly found in the Laramie group, but 

 states that much weight should not be given to this impression won from the 

 study of the very poor material. Mr. Knowlton ventures on no specific names 

 for the fossil forms submitted to him. 



The general relations of the deposit, its degree of induration, and the evi- 

 dence of the fossil plants, slender as it is, suggest that the formation should be 

 equated with the Puget group, and thus belongs in the Eocene. The dips are 

 not often to be read, but they seem to be always rather low, with 30° the observed 

 maximum and 5° to 12° common readings. The strike is highly variable. "We 

 seem, therefore, to have here a relatively little disturbed cap of strata laid down 

 at a date distinctly later than that of the post-Laramie orogenic revolution, 

 which so signally deformed the Cretaceous rocks of this general region of the 

 Cordillera. The thickness of the visible beds totals probably about 1,000 feet. 

 To this group of sediments the name, Huntingdon formation (from the name 

 of the neighbouring village), may be given. Rocks of apparently the same 

 nature and age have been long known as coal-bearing in the Hamilton and lower 

 Nooksak Valley districts south of the Boundary line. * 



Near the southern end of Wade's Trail over Sumas mountain a bench of 

 the Huntingdon conglomerate and sandstone is cut by thin sheets of a greatly 

 weathered porphyry, apparently a syenite porphyry. The relations are obscure; 

 the porphyry may* occur as one or more sills, or as dikes. It is the only eruptive 

 rock known to cut the Eocene formation. The porphyry has not been examined 

 under the microscope. 



* See G. O. Smith and F. C. Calkins, op. cit., page 34. 



