280 



SCIENCE. 



[Vol. I., No. 10. 



The elaborate report ou the fislies, by Pro- 

 fessor David S. Jordau, occupying more than 

 two hundred and fifty pages, gives an interest- 

 ing history' of Ohioan ichth^yology, with de- 

 scriptions of all the species as well as of the 

 principal genera and higher groups. It appears 

 that the fauna has been ^increased from the 

 sixtj'-six species known to Dr. Kirtland (1840- 

 1846) to a hundred and sixtj'-five. A useful 

 tabulated synopsis exhibits in four parallel 

 columns the names admitted by Rafinesque, 

 Kirtland, and Giinther, as well as Jordan. 

 The fauna is also disintegrated into its several 

 elements, — the Lake fauna (26 sp.) , the Ohio- 

 river fauna (37 sp.), and the ' species of gen- 

 eral distribution' (28 sp.) ' As an illustration 

 of the character of the local fauna of the 

 smaller streams of the interior,' a list of the 

 species (68) occurring in the White River, 

 near Indianapolis, is added, with notes as to 

 their comparative abundance or rarity. 



The typography-, although good for a public 

 document, could not be accorded much excel- 

 lence were the work issued hy a private pub- 

 lisher ; and the press-work is verj' unsatisfac- 

 tory-. The synonymy of species is printed in 

 much too large type in the division on the 

 mammals, although afterwards changed. This 

 inequalitj- is unsightly ; and numerous t3-po- 

 graphical errors occur. 



GEIKIE'S GEOLOGICAL SKETCHES. 



Geological sketches at home and abroad. By Archi- 

 bald Geikie, t/L.D., F.R.S., director of the 

 Geological survey of the United Kingdom. 

 New York, Macmillan Sp Co., 1882. 370 p. 8°. 



In this pleasant volume, well illustrated by 

 the author's pencil. Prof. A. Geikie has gath- 

 ered together a number of sketches, essays, 

 and addresses, picturesque, descriptive, ancl 

 historical, published during the past twenty 

 j-ears in various journals, and all written with 

 some reference to the science of geology, of 

 which he has been so successful a cultivator. 

 Some of these papers have little more than a 

 local and popular interest, but are gracefully 

 written, and well suited to give the unsci- 

 entific reader a taste for geological studies. 

 Others have a higher significance, and raise 

 questions which are of importance to all stu- 

 dents of geology, and would require for their 

 adequate discussion more si)ace than we can 

 here command. 



One of the most interesting of these papers 

 is that entitled ' A fragment of primeval 

 Europe,' in which we are introduced to the 

 crystalline rocks of north-western Scotland 



and the adjacent isles. These ancient gneissic 

 and granitoid strata, first critically studied by 

 MacCuUoch, were early recognized as the lith- 

 ological and mineralogical analogues of the 

 primitive gneisses of Scandinavia and parts of 

 North America ; and in 185.5, after the name of 

 Laurentian had been given to the latter, it was 

 suggested that the name should be extended 

 to the similar rocks of Scotland, which Mur- 

 chison had called the fuudameutal gneiss, — a 

 suggestion since adopted. The aspect of the, 

 region occupied by these ancient rocks is pecul- 

 iar. " The whole landscape is one of smoothed 

 and rounded bosses and ridges of bare rock, 

 which, uniting and then separating, enclose 

 innumerable little tarns. There are no defi- 

 nite lines of hill and vallej' : the country con- 

 sists, in fact, of a seemingly inextricable 

 labj-rinth of hills and valley's, which, on the 

 whole, do not rise much above, nor sink much 

 below, a general average level." No peaks 

 nor crags are seen; and "the domes and 

 ridges present everj-where a rounded, flowing 

 outline." The whole area is, according to our 

 author, smoothed, polished, and striated, as 

 if ice-worn, and presents, in fact, a typical 

 glaciated surface. Over this ' tumbled sea 

 of gray gneiss ' rise conical mountains of near- 

 ly' horizontal, dark-red sandstone, capped by 

 white quartzites, the summits sometimes at- 

 taining 3,400 feet above tide-water. Two 

 good woodcuts serve to illustrate the peculiari- 

 ties of this curious landscape. 



These uncrystalline, unconformable beds of 

 Cambrian age, dipping gently eastward, are 

 succeeded bj' fossiliferous limestones belonging 

 to the same period, which, in the same direc- 

 tion,' appear to pass below a series of flaggy 

 gneisses and crystalline schists, the age of 

 which has been a burning question among Brit- 

 ish geologists. The problem regarding them is 

 identical with that which has been raised in 

 New-England geology ; namely, whether the 

 crystalline schists, towards and beneath which 

 the fossiliferous paleozoic rocks l^-ing to the 

 westward are seen to dip, are newer or older 

 than these. Professor Geikie, for Scotland, 

 holds to the former view, and supposes these 

 crystalline rocks in the Highlands to be formed 

 from a subsequent alteration of still younger 

 paleozoic strata : l>ut in Scotland, as in New 

 England, the opposite view is now, by most 

 geologists, held to be established ; namelj-, that 

 the crystalline rocks in question are pre-Cam- 

 brian, and in that sense a part of the ' prime- 

 val ' world. ^ 



Geikie shows that the sculpturing of the 



^ Geological magazine, February, 1883, p. 83. 



