128 Recent Literature. [February, 



transitional though they may appear to us, are not of use to their 

 possessors. But the gradual evolution of a structure not yet become 

 functionally useful, is but a parallel case with the persistence for 

 a long period of structure no longer functionally useful. The 

 wonder is rather, when we review the wondrous changes passed 

 through in the life history of an animal or of a plant, from 

 the seed to the tree, from the egg to the free embryo and thence 

 to adult life, that all works so truly as it does, and that variation 

 is not more frequent The slightest over-development of one 

 organ, or arrest of development of another, caused by the sur- 

 rounding environment or by heredity (the effect of the environ- 

 ment of ancestors) may change the genus, the change may neither 

 be useful or hurtful, yet its tendency is to continue when com- 

 menced, and it may, in process of time, become functionally use- 

 ful. On the other hand, a useful variation may take place sud- 

 denly (as we see in Amblystoma) and a hurtful one is put an end 

 to by the death of the possessor. We commend this book to the 

 notice of our readers. 



Southall's Pliocene Man in America. 1 — The author evidently 

 means well enough in writing this pamphlet, but he appears to ' 

 start with the idea that geology is an exact science, that we know 

 the precise time, even geologically speaking, when the Pliocene 

 epoch ended and the Quaternary began, and that certain haphazard 

 estimates of the time in years that man has been on the earth made 

 by an accomplished zoologist like Mr. A. R. Wallace, who has, 

 however, published little or nothing original upon palaeontology or 

 geology, are of real value. So when ten years ago a " Mr. Vivian 

 and Mr. A. R. Wallace claimed for [man] an antiquity of i,coo,ooo 

 and 500,000 years " we do not see why Mr. Southall or any other 

 man should in 1881, get into a flurry over the matter, unless he 

 wants to make himself conspicuous as a critic of geologists and 

 geological reasoning in general. Confining ourselves to the 

 points of most importance in the query as to the age of Pliocene 

 man, the geologist wants to know the limits of the Pliocene in 

 western America. What Whitney calls Pliocene deposits may 

 be contemporary with the incoming of the glacial period in 

 eastern America, or it may be a transition period between the 

 Pliocene and Quaternary period. As we understand it, the age of 

 those lower level gold-bearing sands and gravels is quite uncer- 

 tain, and they may, contrary to Whitney's opinion, be no older than 

 our eastern boulder clays. Moreover what Mr. Southall overlooks, 

 none of the specimens of human art found on the Pacific coast, in 

 ailed Pliocene deposits, have been taken out either by the 

 in the presence of a geologist, not even of Professor 



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