May 17, 1895.] 



SCIENCE. 



549 



enormous and apparentlj' sudden changes 

 in organic forms which took place dui-ing 

 and at the end of the Permian period. 



4. In connection with the last he accepts 

 also the idea of a laud-connection (Gond- 

 wanaland) between India and Soidh Africa, 

 and perhaps indirectlj' through the en- 

 larged Antarctic continent — with Australia 

 — in Permian and Triassic times, as evi- 

 denced by the great similaritj' of the plants 

 and the reptiles of that time in these now 

 widely separated countries. It is true that 

 there is very deep sea between these points 

 now ; but it is possible that the idea of the 

 permanence of deep sea basins, originated 

 by Dana, may have been pushed a trifle too 

 fer by "Wallace as a means of separating 

 faunas and floras. 



o. He does not accept Algonkian as a 

 system of rocks coordinate with Palaeozoic 

 and Mesozoic, but regards these pre-Cam- 

 brian strata as the upper part of the 

 Archaean, i. e., as Huronian and upper 

 Laurentian. Perhaps the time is not yet 

 come to settle this question definitely. 



6. He accepts as probable the existence 

 in Quaternarj- times of a greatly elevated 

 and enlarged Antarctic continent, connect- 

 ing with and connecting together the south- 

 em parts of South America, South Africa 

 and Australia similar to that of Permian 

 times, as evidenced by the faunas, and as 

 accounting for the Quaternary glaciation 

 of these regions. 



7. He agrees with Hilgard in thinking 

 that the LaFayette formation (many geo- 

 logists seem to forget that we owe this 

 name to Hilgard) is a torrential rirer de- 

 posit of the early Quaternary and not a 

 marive deposit of the Pliocene times as 

 maintained by McGee, and that therefore it 

 indicates elevation and not depression of 

 the continent. 



8. He does not accept Croll's theorj- of 

 the cause of the glacial climate ; but, along 

 with most American geologists, regards it as 



mainlj' due to elevation of northern land. 

 This would not only directly increa.se the 

 cold in high latitude regions, but would in- 

 directly increase the ice-accumulation by 

 connecting America and Europe in these 

 regions and thus limiting the northward 

 extension of the Gulf Stream, which, circu- 

 lating around the Atlantic in mid-latitude 

 regions, would furnish abundant warm 

 vapors to be condensed as snow on the 

 elevated northern laud. 



9. As might have been expected, his dis- 

 cussion of mountain-making is masterly. 

 But one is interested, though not surprised, 

 to observe that he does not accept the recent 

 theories of Reade, Dutten and others as to 

 the cause of mountain formation, but still 

 regards the contraction-theory in some form 

 as more probable. 



But a reviewer is ' nothing if not critical.' 

 I must vindicate my character as reviewer 

 by finding some faults, even though they be 

 trifling. 



10. This edition, we observe, drops out 

 the graphic illustrations of the distribution, 

 in time, of families, orders and classes of 

 animals, which constitutes so conspicuous, 

 aud, we may add, so attractive a feature of 

 previous editions. We observe also that 

 the index of authors quoted and of those 

 from whom figures are taken is omitted. 

 This is to be regretted in a work which 

 will be so constantly refeiTed to. 



1 1 . "We observe also a few errors of over- 

 sight or of misunderstanding of authors 

 quoted. On page -359, and again on page 

 .380, he gives, on King's authority, the whole 

 thickness of "W^ahsatch sediments, from the 

 Cambrian to the Laramie inclusive, as .31,- 

 000 feet. In fact. King gives between 31,- 

 000 and 32,000 for the Paheozoic alone, page 

 122; and in addition 3,800 feet for Jura- 

 Trias, page 537, and 12,000 feet for the Cre- 

 taceous, page 539 (49th parallel, Vol. 1). 



Again, he states on page 520 that the oldest 

 known insect — Protocimex — is found in the 



