5. On a new Species of Loftusia from British Columbia. By George M. Dawson, D.S., Assoc. R.S.M., F.G.S., of the Geological Survey of Canada. (Read June 5, 1878.)
[Plate VI.]
In 1869, Dr. W. B. Carpenter and Mr. H. B. Brady described, in the 'Transactions' of the Royal Society, two remarkable types of gigantic arenaceous Foraminifera, under the generic names of Parkeria and Loftusia. For the description of the latter form Mr. Brady is more particularly responsible, and to the genus then created by him I have now to add another species, for which the name of Loftusia Columbiana is proposed.
The original specimens of Loftusia were obtained many years ago by Mr. W. K. Loftus in Persia. They were referred to in his paper on the geology of the Turco-Persian frontier and districts adjoining, published in the Quarterly Journal of the Geological Society in 1855, but remained undescribed till they came into Mr. Brady's hands. From the geological descriptions by Mr. Loftus, and other forms of Foraminifera found in the same stones, Mr. Brady believes the geological position of Loftusia persica to be in the oldest Tertiary rocks.
The specimens now to be described are from the interior of British Columbia, and their age is, I believe, Carboniferous. Examples of the form were first collected by Mr. J. Richardson, of the Geological Survey of Canada, in 1871, and are mentioned in the Report of Progress for 1871-72. About a year ago, I examined Mr. Richardson's specimens with some care; but during the past summer, having opportunity to visit the locality from which they were procured, the occasion was taken to collect a large number of additional specimens, representing all varieties of appearance and preservation. Mr. Thomas C. Weston has prepared from these and Mr. Richardson's specimens a number of transparent sections, from which the accompanying descriptions and drawings have been made.
Most of the specimens are from Marble Canon, a remarkable valley which runs through from the banks of the Fraser River to the bend of Hat Creek, with a direction nearly transverse to that of the main features of the country. For a distance over ten miles, the sides of the valley are formed almost continuously of mountains of limestone or marble. The first impression is that an immense thickness of limestone is represented in the exposures; but, although the dips are too obscure to allow the attitude of the beds to be worked out throughout the length of the Canon, some small sections show that part at least of the beds have been sharply folded and the whole series of folds overturned. This being the case, it may be that a comparatively thin limestone or series of limestones forming a succession of folds superimposed on a broad anticlinal flexure account for the appearance presented. That the limestones have a very considerable thick-
