Terraces and River Valleys — Speneer. 165 
"the plan of the earth may be attributed to the continual 
foundering of the earth's external shell," a place for which 
may be found later, but is not necessary at least at this 
time. 
Whatever the explanations of the great land valleys 
extending across the continental shelf and down the con- 
tinental slope, to Prof. Hull is due the honor of assembling 
these great phenomena together, and showing that in a 
general way they belong to the same cause, and so far as 
has been ascertained have been fashioned by atmospheric 
and river erosion. The reviewer regards the difficulty of 
such acceptance as not in their form but in the conse- 
quences of such phenomena, for they are universal. Their 
development requires more time than is popularly assigned 
to the late geological periods. This impression will have 
to give way to the evidence, if not sustained. Doubtless 
adjustments will be obtained on this point. We do not 
know the causes of changes of level, nor do we need to 
wait till then to accept the facts. Were the phenomena 
alternating? The continental shelves seem to challenge 
such assumption ; if sychronous then an incomprehendible 
change of hydrosphere or lithosphere, or ]:)oth, or a de- 
pression of the ocean's bed — even the enormous changes 
of level of the Asiatic plateaus in recent times we accept 
without understanding them. The facts of the submarine 
valleys are now too well established to set aside because 
we do not know more about them. They form a new 
chapter carrying us further in the unknown history of the 
surface features of the earth. We are particularly fortu- 
nate in having this work done by the author of the "Geolo- 
gical Survey of Western Palestine."* who as already men- 
tioned, has studied the remarkable Jordan-Arabah valley. 
Returning now to Prof. Hull's contributions we find 
"The Physical History of the Norwegian Fjords. "t The 
fjords are described. P>ut we shall pass on. As to their 
origin "the fjords are primarily the outcome of rain and 
river erosion, continued through long ages of geological 
* With Special Reference to the Mode of Formation of the Jorrlan- 
Arabah Depression and the Dead Sea." Pub. by the Palestine Explor. 
Fund, I^ondon, 1889. 
t Loo. clt. 
