240 Correspondence-^Mev. H. H. Wimcoorl. 



Browne calls attention to my omission to mention this band, he must 

 have overlooked the circumstance that he has forgotten to notice tho 

 far more important Calcarian which intervenes between the Oxfordiau 

 and the Cornbrash, and which is one of the best known and most 

 widely spread subdivisions of the Jurassic system. 



March Uth, 1885. W. T. Blanford. 



GEOLOGICAL AGE OF THE ROCKY MOUNTAINS. 



Sir, — A recent conversation with Dr. Hicks induces me to send 

 you the following recoi'd of the results of a short ramble in the 

 Eocky Mountains, which I trust you may deem of sufficient import- 

 ance to insert in your Magazine. 



On a much-to-be-remembered morning on the 11th of last Septemr 

 ber, Professor Selwyn and Dr. G. M. Dawson of the Canadian 

 Geological Survey, with several other brothers of the hammer, left 

 the cars of the Canadian Pacific Eailway at Stephen, for a walk 

 down the track into British Columbia. Passing the picturesque 

 little lake on the summit of the Kicking Horse Pass, between 5000 

 and 6000 feet above sea-level, the rocks on the right hand of the 

 track were carefully examined for any indication of their age. They 

 consisted for the most part of a series of almost vertical calcareous 

 and quartzite beds, followed by greenish slates and were varied in 

 colour, blue, white and green predominating. Though supposed to 

 be altered Devonian, yet we failed to obtain any fossil evidence to 

 determine this point. After however crossing the high trestle- 

 bridge spanning the torrent which gives its name to the pass, we 

 were more fortunate, and found sufficient evidence whereby the age 

 of these beds could be clearly defined. Eemaining behind the rest 

 of the party, my attention was attracted to a greenish micaceous slab 

 of rock dipping at a high angle to the east, bearing on its face those 

 fucoidal markings, or worm-tracks (?), so abundant in the Ilfracombe 

 beds in North Devon, and on detaching some of these, I soon saw 

 other and more important black patches, the organic nature of which 

 there could not be any doubt about. These at first sight were con- 

 sidered to be the shields of Trilobites. Proceeding onwards about 

 62 yards on the same side, a dense blue calcareous band M'as found 

 almost vertical about six inches thick divided from another of the 

 same kind about seven inches thick by a parting of greenish shale ; 

 both these were full of organisms. On showing them to Prof. Boyd 

 Dawkins and others, they were at once pronounced to be Primordial. 



Since my return home. Dr. Hicks has examined my specimens, 

 and states that they represent a Menevian fauna, and that the mica- 

 ceous rock contains lime and is detrital, with the tail of a Paradoxidcs 

 on its surface, whilst the dense blue calcareous bands have abundant 

 fragments of Paradoxides, Conocoryphe and other allied forms. This 

 fact is of value, as it proves that a Primordial zone exists north of 

 the 49th parallel of latitude, and somewhere between the 116th and 

 117th parallels of longitude, a fact which has been, I believe, hitherto 

 denied or at least unproved. H. H. Winwood. 



Bath, udpril 17, 1885. 



