"The united thickness," says Sir William Logan, "of these three great series, the Lower and Upper Laurentian and Huronian, may possibly far surpass that of all succeeding rocks, from the base of the Palæozoic to the present time. We are thus carried back to a period so far remote that the appearance of the so-called Primordial fauna may be considered a comparatively modern event."[25] So great a revolution of thought, and this based on one fossil, of a character little recognisable by geologists generally, might well tax the faith of a class of men usually regarded as somewhat faithless and sceptical. Yet this new extension of life has been very generally received, and has found its way into text-books and popular treatises. Its opponents have been under the necessity of inventing the most strange and incredible pseudomorphoses of mineral substances to account for the facts. As might have been expected, after the publication of the original paper, other facts developed themselves. Mr. Vennor found other and scarcely altered specimens closely allied to the Laurentian forms in the Hastings series of Tudor, probably of Huronian age. Gümbel recognised the organism in Laurentian rocks in Bavaria and elsewhere in Europe, and discovered a new species in the Huronian of Bavaria.[26] Eozoon was recognised in Laurentian limestones in Massachusetts[27] and New York, and there has been a rapid growth of new facts increasing our knowledge of Foraminifera and other humble animals in the succeeding Eozoic and Palæozoic rocks. Special interest attaches to the discovery by Mr. Vennor, and by Walcott and Matthew, to be mentioned in the sequel, and tending to bridge over the interval between the Laurentian fossil and those of the Lower Cambrian. Another fact, whose significance is not to be over-estimated, is the recognition both by Dr. Carpenter and myself of specimens in which the canals are occupied by dolomite or by calcite like that of the organism itself I have made several visits to the locality at Petite Nation originally discovered by Mr. Lowe, in company with Dr. Carpenter, Dr. Bonney,[28] and other skilled observers, and have very carefully studied all the facts with reference to the mode of occurrence of the forms in the beds, and their association with layers of fragmental Eozoon, and have found that these are strictly in accordance with the theory that these old Laurentian limestones are truly marine deposits, holding the remains of the sea animals of their time. [Footnote 25: _Journal Geological Society_, February, 1865.] [Footnote 26: _Ueber das Vorkommen von Eozoon_, 1866.]