Reviews—A. Blytt—Displacement of Beach-lines. 219 
beds, and in the formation of beach-lines, terraces, and moraines. 
To each period of precession there corresponds one alternation of 
Strata. 
In order to illustrate this portion of the subject, the author 
institutes a comparison between astronomical periods and the 
different series of geological strata. We may pass briefly over this 
portion of the subject. Suffice it to say that calculations have been 
made of the curves of the eccentricity of the earth’s orbit. These 
curves or fluctuations are repeated once in about every 14 million 
years. The eccentricity has been calculated for a period of 45 
million years, with the result that three curves are indicated. In 
each of these cycles of 14 million years, the author finds 16 arcs 
of the curve, which correspond with certain oscillations in the eccen- 
_ tricity of the earth’s orbit. 
The change in the tidal-wave caused by the variation of the 
eccentricity is presumed to be sufficiently great to explain the dis- 
placement of beach-lines. Hach are of the curve before mentioned 
corresponds to one oscillation of the sea. For every considerable 
oscillation of the beach-lines there is a corresponding geological 
stage. In these stages there will be found a certain number of 
alternations of strata, as many in fact as there are periods of pro- 
cession in the corresponding arc. 
The author remarks that the oscillation of beach-lines, correspond- 
ing to an are, cannot be pointed out everywhere, but only in those 
geological basins where the forces at the time exerted their effect. 
In the Hampshire and Paris Basins he finds the total number of 
alternations in the strata to be about the same; and he endeavours 
to illustrate this by noting the number of alternations he finds 
in the different subdivisions of the Tertiary strata. One quotation 
will suffice to illustrate the method of the author. He remarks:— 
“The Upper Eocene Barton Clay has 5 layers of septaria. It is 
synchronous with the Gres de Beauchamp of the Paris basin, and it 
must consequently, like this, correspond to the are 14 of the curve. 
This are represents 100,000 years, and, consequently, about 5 periods 
of precession.” 
We must confess our utter disagreement with the author in his 
interpretation of geological facts. 
As before mentioned, septaria afford no clue to changes in the 
physical conditions attending deposition. Again, the author remarks 
that ‘‘ between the Eocene and the Oligocene a great break exists in 
the Isle of Wight,” and he proceeds to remark that this may repre- 
sent about 200,000 years. Now as a matter of fact there is no 
physical break between these divisions in the Isle of Wight. More- 
over, the Tertiary strata are for the most part so variable in character, 
that it is not always possible to correlate particular layers exposed 
in the cliffs on the east side of the island with those seen on the 
west. What, then, is the value of the author’s contention that the 
Hocene period appears to have had 16 oscillations, and should corre- 
spond to the first cycle, extending from 3,250,000 till 1,810,000 years 
before the present time ? We fear the only verdict that can be given is, 
