618 



SCIENCE. 



[N. S. Vol. XVII. No. 433. 



lying in the line of this interchange would 

 be settled by Scandinavian, boreal-Ural and 

 alpine-Carpathian plants. Naturally, also, 

 during the fluctuations of the last glaciation, 

 and especially during the retreat of the ice, 

 a mixture of the highest forest and lowest 

 subalpine societies would take place. 



Traces of the steppe period, exemplified in 

 the dry hiU and rock plants, correspond with 

 the ' prsealpine ' societies that occur on the 

 limestone and dolomite slopes of the northern 

 Alps. If we picture to ourselves the time 

 when, after the warm interglacial period, a 

 later glaciation took place, it must be taken 

 for granted that the prsealpine grove and rock 

 plants were driven down before the ice and 

 settled on other limestone hills at a lower 

 level. These afterwards mixed in various 

 places with plants of Pontic origin, which also 

 chose dry marl and calcareous soils to settle 

 on. These Pontic elements came in from the 

 east along paths which may still be traced 

 with a considerable degree of assurance. 

 Thus along the Elster, the plants of the Saale 

 (including various prsealpine and Pontic spe- 

 cies) are not most thickly distributed simply 

 where there is the greatest extent of limestone 

 rocks, but rather in places that these plants 

 could most easily reach, and this depends on 

 the position of valleys free from forests. 

 Along the shortest line from the Saale to the 

 Elster extends a plateau of muschelkalk, and 

 it is exactly in this direction to the eastward 

 that the hills on the Elster reproduce most 

 fully on their south and west sides the flora 

 of the hills along the Saale. Thus the natural 

 geographical paths for post-glacial settlement 

 have been reinforced by favorable edaphic 

 and climatic conditions, and all of these must 

 be taken into consideration in attempting to 

 account for the history of the present Her- 

 cynian flora. But until the geological history 

 is more fully and certainly known it is im- 

 possible to construct, with any hope of accu- 

 racy, such a system as, for example, that at- 

 tempted by Schulz, who assumes four periods 

 of warmth alternating with as many of gla- 

 ciation, and undertakes to trace the periods 

 and course of immigration for single species. 



Since the glacial period the orographic fea- 



tures of Hercynia have not been essentially 

 altered, and then, as now, climatic and eda- 

 phic factors were together determining the 

 immigrations of plants. It is very probable 

 that at the time of the Pontic invasion the 

 region of the lower Saale had a more dis- 

 tinctly steppe climate than other parts of 

 Hercynia, and that the triassic soils which 

 to-day favor the plants inhabiting them of- 

 fered corresponding advantages to such set- 

 tlers then. In manifold other ways the con- 

 tinuity of present with past physiographic 

 conditions becomes increasingly obvious, and 

 the present study is a noteworthy recognition 

 of the necessity of admitting this principle 

 to the fullest extent in attempting to con- 

 struct a satisfactory picture of the historical 

 succession of plant societies. The attainment 

 of such an ideal, though beset with extraor- 

 dinary difficulties, is being brought nearer 

 through the indefatigable labor embodied in 

 this_ and the companion volumes of the ' Vege- 

 tation der Erde.' V. M. Spalding. 



The Archeological History of Ohio. By Ger- 

 ard EowKE. Columbus, O. Published by 

 the Ohio State Archeological and Histor- 

 ical Society, 1902. 8, XVI. 

 Mr. Fowke's book is not written, so he 

 claims, for scientists or specialists, but to 

 give laymen an idea of the extent and char- 

 acteristics of the prehistoric remains found 

 within the borders of the state of Ohio. It 

 fulfils its mission and presents in its Y60 pages 

 a complete resume of all the antiquities of 

 the state, and also refers to nearly every pub- 

 lication upon the subject. The work is well 

 done, and as Mr. Fowke compassed a task 

 which required a great deal of time, and 

 would not have been possible to any person 

 who had not studied the Ohio field, as he 

 has, for twenty years, he is deserving of our 

 meed of praise. 



But while the above is true, the book itself 

 may not further the study of archeology in 

 the United States. Unfortunately the author 

 is even more than controversial, he is dog- 

 matic, and to most of the writers and authori- 

 ties on Ohio antiquities, he is unjust. Such 

 a book as this is, evincing years of study in 



