Those, then, whose opinions on such a subject deservedly carry the greatest weight, are decisively of opinion that we are presented in the _Eozoön_ of the Laurentian Rocks of Canada with an ancient, colossal, and in some respects abnormal type of the _Foraminifera_. In the words of Dr Carpenter, it is not pretended that "the doctrine of the Foraminiferal nature of _Eozoön_ can be _proved_ in the demonstrative sense;" but it may be affirmed "that the _convergence of a number of separate and independent probabilities_, all accordant with that hypothesis, while a separate explanation must be invented for each of them on any other hypothesis, gives it that _high probability_ on which we rest in the ordinary affairs of life, in the verdicts of juries, and in the interpretation of geological phenomena generally." It only remains to be added, that whilst _Eozoön_ is by far the most important organic body hitherto found in the Laurentian, and has been here treated at proportionate length, other traces of life have been detected, which may subsequently prove of great interest and importance. Thus, Principal Dawson has recently described under the name of _Archoeosphoerinoe_ certain singular rounded bodies which he has discovered in the Laurentian limestones, and which he believes to be casts of the shells of _Foraminifera_ possibly somewhat allied to the existing _Globigerinoe_. The same eminent palæontologist has also described undoubted worm-burrows from rocks probably of Laurentian age. Further and more extended researches, we may reasonably hope, will probably bring to light other actual remains of organisms in these ancient deposits. THE HURONIAN PERIOD. The so-called _Huronian Rocks_, like the Laurentian, have their typical development in Canada, and derive their name from the fact that they occupy an extensive area on the borders of Lake Huron. They are wholly metamorphic, and consist principally of altered sandstones or quartzites, siliceous, felspathic, or talcose slates, conglomerates, and limestones. They are largely developed on the north shore of Lake Superior, and give rise to a broken and hilly country, very like that occupied by the Laurentians, with an abundance of timber, but rarely with sufficient soil of good quality for agricultural purposes. They are, however, largely intersected by mineral veins, containing silver, gold, and other metals, and they will ultimately doubtless yield a rich harvest to the miner. The Huronian Rocks have been identified, with greater or less certainty, in other parts of North America, and also in the Old World.