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Show 353 from the other bed at Nanaimo being, so far as determined, all new species, and belonging apparently to genera common to the Cretaceous and Jurassic systems, some doubts were entertained whether or not they might belong to the latter; though it was stated that from their general characters and affinities, it appeared mere probable that they belonged also to the Cretaceous. On looking them over some time after, however, the writer was led to suspect that they might be of Jurassic age, which suggestion was mentioned to Dr. Newberry, who referred to it in his report on the geology of Captain Williamson's Pacific Railroad Survey. A review of the whole subject, however, with the aid of the additional light derived from the more extensive collections brought in by the Northwestern Boundary Survey, fully confirmed the original conclusion that the whole belong to the Cretaceous. One of the strongest evidences of this is the occurrence, in these beds at Nanaimo, of numerous dicotyledonous leaves, of so modern an aspect that some who have examined these leaves alone, without regard to the associated molluscan remains, have even thought that these beds ought to be referred to the Tertiary. * That they do not belong to the Tertiary, however, is evident from the fact that they also contain a large species of Inoceramus and a Goniomya, together with Cretaceous types of Trigonia and Pholadomya. The Nanaimo locality is " on the eastern shore of Vancouver's Island, and Komooks, or Komax, t which is also on the eastern shore of the same, is about sixty to seventy miles farther northwest; while the Sucia Islands are in the Gulf of Georgia, about the same distance in a southeast direction from Nanaimo. At the Nanaimo locality, the beds consist of sandstone, good coal, and conglomerates, composed of small pebbles, with seams of greenish- gray and brownish beds of arenaceous matter containing fossils, the whole dipping eastward. The same beds also occur on the neighboring Douglass and New Castle Islands, where they likewise contain coal. These beds seem to be quite distinct from those at Komooks and on Sucia Islands, both in their fossils and in their lithological characters; and from the affinities of. their fossils, as as well as from the direction of the dip of the strata, I am inclined to believe them older than those seen on the Suica Islands and at Komooks, though the whole seems to belong to division A. of the California reports. The Nanaimo beds do not seem to be equivalent to any of the subdivisions recognized in the Upper Missouri country. The Komooks and Sucia Island beds, however, appear, both from the affinities of their fossils, and from the state of preservation of the latter, to be related to what we have called the " Fort Pierre group", or division No. 4 of the Upper Missouri section. In the latter district, this division is composed mainly of dark plastic and indurated clays, in which the fossils often occur enveloped in hard concretions, and show the substance of the shells in a beautiful state of preservation. Those from Komooks and Sucia Islands are in a similar state of preservation, and appear to have been enveloped in similar concretions; while the specimens from Nanaimo are maiuly casts, or, where they retain any portion of the shell, it is more decomposed and has an older look. Among the species from Komooks and Sucia Islands, some of the Bacu-tites and a Nautilus are related to species found in No. 4 of the Upper Missouri, while one of the Ammonites and one of Inoceramus appear scarcely to differ more than as varieties from forms found in the horizon mentioned in the Upper Missouri. • These plant- remains have been investigated by Dr. Kewberry, and by him referred to the Cretaceous. t Mr. Gabb writes this name " Komax " in the California report. |
