Makch 30, 1883.] 



SCIENCE. 



2-19 



where the fossiliferous beds of the Potsdam rest 

 horizontally on the upturned edges of the Keweenian, 

 and are made up, in part, of its ruins. Parts 1 and 

 6 of the third volume of the Geology of Wisconsin 

 (ISSO) will show the accumulation of evidence with 

 regard to the stratigraphical relations of the Kewee- 

 nian; and few will be found to-day to question the 

 propriety of the conclusion announced by me in 1873, 

 and subsequently by Major Brooks in 1S75, that the 

 copper-bearing rocks of northern Michigan constitute, 

 in his words, " a distinct and independent series, 

 marking a definite geological horizon," which has 

 been designated the Keweenan series, Keweenawan, 

 or, more euphoniously, Keweenian. 



These rocks, so carefully studied by Brooks and 

 Pumi^elly on the south shore of Lake Superior, and 

 largely displayed on Isle Eoyale, Michipicoton Island, 

 Mamainse, and Pointe Aux Mines, on the north shore, 

 were by Logan supposed to be the same with the red 

 and white sandstone and marls, with dolomites and 

 brine-springs, found along Nipigon Bay, Black Bay, 

 and Thunder Cape. He recognized beneath these, in 

 this region, the black slates, etc. {1 of Selwyn), which 

 Logan supposed to form a lower subdivision of what 

 he called the upper copper-bearing series, to distin- 

 guish it from the lower copper-bearing or Huronian 

 series, which is overlaid iinconformably by these 

 black slates. 



This lower subdivision, which I have called the 

 Animikie group, though seen at Thunder Cape be- 

 tween the Huronian and the Nipigon series, is want- 

 ing in Black Bay, where Logan found the latter to 

 rest directly upon the Laurentian ; and also, accord- 

 ing to Bell, on Lake Nipigon, where the Nipigon 

 series reposes on Laurentian and Huronian. Apart 

 from the evidence of its distinctness deducible from 

 the absence of the Animikie in this area at the base 

 of the Nipigon series, I have described a locality near 

 Silver islet, where the basal beds of the Nipigon, rest- 

 ing upon the Animikie, hold pebbles of the character- 

 istic rocks of the latter. 



The mineralogical and lithological characteristics 

 of the Nipigon rocks diifer so much from the Kewee- 

 nian as to create a suspicion that they may belong to 

 two distinct series. In this connection an observation 

 of Macfarlane is important. He found the true Ke- 

 weenian at Mamainse to be uncomforni ably overlaid 

 by a series of bluish sandstones and shales unlike 

 those of the St. Mary series, and, on the contrary, 

 closely resembling those of the Animikie group, to 

 which he compares them. A summary of the evi- 

 dence regarding these rocks will be found in my Azoic 

 rocks {Sd geol. survey of Penn, report E, pp. 230-241). 



Meanwhile, it may be regarded as established that 

 we have, in the Lake Superior basin, (1) the Kewee- 

 nian or cupriferous series, resting unconformably 

 upon the Huronian and other crystalline rocks, and 



(2) lower Cambrian (Potsdam) strata lying uncon- 

 formably upon the Keweenian. We have, moreover, 



(3) the Animikie and (4) the Nipigon group, — two 

 series of strata distinct from each other, and appar- 

 ently from both of the preceding divisions. The ob- 

 servation of Macfarlane makes it probable that the 

 Animikie belongs to a series newer than the Kewee- 

 nian; in which case the lithological unlikeness of the 

 still younger Nipigon group both to the Cambrian 

 and the Ordovian (Siluro-Cambrian) rocks of the 

 Lake Superior basin, would, as I have remarked in 

 the report just cited, raise a suspicion that these red 

 and variegated sandstones and marls, with dolomites 

 and brine-springs, which we have called the Nipigon 

 group, may belong to a higher geological horizon. 



The name of the Quebec group was, as is well 



known, given by Logan to what, under the name of 

 upper Tacouic, had been long before described by 

 Emmons as a great development of strata of the age 

 of the calciferous and Potsdam divisions of New York. 

 In the disturbed belt where this series is displayed, 

 from the lower St. Lawrence to the Hudson-river 

 valley, and beyond, it is now well known that there 

 are included, besides rocks of this horizon, others of 

 Trenton-Loraine (Ordovian) and of lower Helderberg 

 age, together with older rocks, embracing the lower 

 Taconic of Emmons and the still more ancient crys- 

 talline (Huronian) schists called by Logan 'altered 

 Quebec group.' So far as known, there is nothing 

 in this belt of disturbed, faulted, and often inverted 

 strata which can be taken to represent the great 

 Keweenian series. Logan, however, assumed the St. 

 Mary sandstone to be of the age of the Chazy divis- 

 ion of the New- York series, and then proceeded to 

 call the underlying Keweenian calciferous or Quebec 

 group, suggesting that the Kamanistiquia slates 

 (Animikie series) might represent the Potsdam. 

 These references, so far as regards the Chazy and 

 calciferous, are embodied in Logan's maps of 1864 

 and 1866. 



This view, which was never any thing more than a 

 crude speculation, was soon shown to be untenable 

 jjy the establishment of the Potsdam age of the sand- 

 stones overlying the Keweenian, both in Wisconsin, 

 as we have already seen, and in northern Michigan, 

 where Eominger finds these upper sandstones to be 

 overlaid by calciferous and Chazy beds. 



Unless we assume that every thing uncrystalline 

 below the Trenton group is to be relegated to the 

 Cambrian, there is no ground as yet for extending 

 this name to the Keweenian; while the convenience 

 of having a distinctive appellation for this vast met- 

 alliferous series will assure the name Keweenian a 

 distinct and permanent place in geological nomen- 

 clature. T. Stebky Hunt. 



Montreal, March 3, 18S3. 



THE AINOS OF JAPAN. 

 The following is an extract from an article on 

 Yezo, in the transactions of the Berlin Gesellschaft 

 fiir erdkunde, 1883, No. 1. The article was written 

 by Professor Dr. Brauns of Halle, who, during his 

 recent geological exciu'sion to Yezo, visited the large 

 settlement of Saghalin Ainos, in the neighborhood 

 of Sapporo. 



The Aino race belongs to a type entirely different 

 from that of the Japanese, to whom they are now 

 subject. The fear that the number of the Ainos is 

 diminishing, in consequence of the immigration of 

 the Japanese into Yezo, to an extent that would soon 

 lead to their extinction, is not well founded. Accord- 

 ing to the estimate of the Japanese government, the 

 total number of Ainos in Yezo, Saghalin, and the 

 Kurile islands, is less than 18,000. While some 

 authors have accepted tliis estimate, others have set 

 the number of Ainos in Yezo alone as high as 50,000, 

 which, with the addition of those now living under 

 Russian control in Saghalin (from 10,000 to 12,000), 

 and in the southern part of Kamtschatka, would give 

 a total of from 60,000 to 70,000. Although the latter 

 estimate, which is based on a number of reports from 

 different sources (e.g., the missionaries of Hakodate), 

 comes nearer the mark, still the number of Japanese 

 who have settled in Yezo is already greater than that of 

 the Ainos. The Japanese government reports 100,000 



