Dr. C. Callaway — On the Arc/man Bocks. 349 



some of tlie older geologists have expressed much scepticism on the 

 possibility of arriving at satisfactory conclusions. At the outset we 

 are met by the almost entire absence of fossils. In the British 

 Islands not a single oi'ganism, or trace of organism, has been 

 detected in undoubted Archaean rocks. Besides this, the excessive 

 contortion vv'hich many of these ancient deposits have undergone has 

 sometimes proceeded so far as to invert the succession, the older 

 rocks overlying the younger. In some cases metamorphism has 

 been so extensive as to entirely obliterate all trace of bedding. To 

 crown all, Archaean districts are usually shattered by faults, frag- 

 ments of various formations being thrown together in the wildest 

 confusion, as if the mythical giants who heaped Pelion and Ossa on 

 Olympus had been playing at bowls with torn-up fragments of the 

 earth's pavement. Notwithstanding these difficulties, despair of 

 success would be fatal to scientific progress, and what has been 

 done is a sufficient encouragement to further investigation. It is 

 proposed in this paper to examine how far the usual tests of 

 geological age are applicable to these altered and broken formations. 

 The evidence of organic remains is usually of first importance, but 

 here it is rarely applicable. The testimony of Eozoon Cana dense 

 will of course occur to every one. But here we are met by two 

 questions: 1. " Is £Jozoo?i organic ? " 2. "If organic, is it charac- 

 teristic of any one horizon ? " The answer to the first question 

 must be, in the writer's opinion, " Not proven." The most eminent 

 specialists cannot agree in their conclusions. Writer after writer 

 arises with the assured conviction that he has settled the matter, 

 yet the matter refuses to be settled. Whatever may be the ultimate 

 conclusion of science — if such a goal be ever reached — it is obvious 

 that, so long as the organic nature of Eozoon remains undetermined, 

 the structure can possess no decisive value for classificatory purposes. 

 But, admitting that Eozoon is a true fossil, is it characteristic Of any 

 one epoch ? Is it Laurentian, and Laurentian only ? The researches 

 of American geologists tend to prove that such is not the case. In 

 Hastings County, Ontario, is a great series of " slates, quartzites, 

 conglomerates, and limestones." These rocks are said to rest 

 unconformably upon the edges of both the Laurentian and the 

 Huronian, and the conglomerates contain pebbles supposed to be 

 derived from those formations. In the upper part of the series are 

 " fine-grained, greyish, more or less schistose, and earthy limestones, 

 containing Eozoon." This group is referred to the Taconian, one of 

 the higher Arch^an formations. This succession was worked out 

 by Mr. Vennor, and adopted by Dr. Sterry Hunt. The lithology of 

 the rocks is widely different from either the Laurentian or the 

 Huronian, and there seems no sufficient reason to doubt their 

 posterior age. Accepting this view, the value of Eozoon Canadense 

 as a test of contemporaneity is at once destroj'^ed. The late Sir K. I. 

 Murchison felt no difficulty in admitting that the fossil might even 

 be "Lower Silurian." When it was announced that Eozoon had 

 been found in the serpentinous marble of Connemara, he said : — 

 " Even if it should be proved that the foramiuifer is present, its 



