308 
and the redemption of the desert along ir- 
rigated valleys afford material for an enter- 
taining narrative by Fernow (Nat. Geogr. 
Mag., VIII., 1897, 203-226). Much of the 
lower ground is desolate, unless exceptional 
rains allow a temporary growth ; but the 
few valleys of streams large enough to feed 
irrigating canals contain green groves, Or- 
chards and fields. The higher plateaus and 
volcanoes bear forests of open growth; 
about Flagstaff 12,000,000 feet of lumber 
are cutannually. The open grouping of the 
trees is ascribed to variation in water stor- 
age by the soil. Although millions of pine 
seedlings spring up after the rains, all of 
them perish from frost, unless the season is 
exceptionally favorable. The young tree 
growth does not follow in annual genera- 
tions, but in irregular periods of from three 
to ten years. Open grassy glades of fine 
black loam seem to mark the site of ex- 
tinguished lakes. Brief account is given 
of an ascent of San Francisco mountain and 
of a visit to the Grand Canyon of the Colo- 
rado, but it seems rather negligent of the 
rest of the world to speak of even the unrival- 
led canyon as ‘a thought of God on earth ex- 
pressed.’ 
TRANSVERSE VALLEYS IN THE JURA. 
A NEw contribution to the above much- 
discussed question is made by Dr. Fr. J enny, 
(Das Birsthal: ein Beity.g¢ zur Kenntniss 
der Thalbildung in Fal.engebirge, Basel, 
1897), with the conclusica that the several 
transverse valleys or cluses of the Birse are 
the result of backward josion along lines 
of local distortion in the ‘anticlinal ridges, 
whereby the river course has become more 
or less adjusted to the structure of the re- 
gion. It is argued that in the early stages 
of folding, the drainage was consequent, 
and that several temporary lakes were then 
formed. 
arches defined the river course. ‘ The 
Birse has gained its present course by a 
SCIENCE. 
Local deformation in the growing’ 
[N.S. Vox. VI. No. 140, 
change from its original path through ad- 
justment to the structure of the mountains 
that it traverses.” 
It is not clear whether the author advo- 
cates the diversion of early consequent 
streams to transverse courses by the head- 
water growth of diverting streams or not; 
no explicit statement being made on this 
point. The antecedent origin of the rivers, 
advocated by Foerste and Rollier, is dis- 
carded. Yeta qualified antecedent origin 
is implied, for the present river course is 
given an early date, before the folding was 
nearly completed ; as if consequent on the 
early folding and antecedent to the rest. 
The value of adjustment to internal struc- 
tures in locating the river seems exaggerated. 
Even if essentially antecedent, the slight 
adjustments now found within the cluses 
might have taken place as the valleys were 
deepened. Moreover, it is highly probable 
that slight irregularities of structure, such 
as those to which Jenny ascribes the loca- 
tion of the existing cluses, would have been 
found wherever the cluses had been cut 
down across the anticlines. The frequent 
occurrence of cluses near the end of pitch- 
ing anticlines is quite as suggestive of a 
course consequent upon initial folding and 
antecedent to later and greater folding as 
of dependence on slight local deformations. 
SUB-OCEANIC CHANGES. 
Mityne draws attention to sub-oceanic 
changes (London Geogr. Journ., X., 1897, 
129-146) caused by slides of detritus down 
the marginal slopes of continental plateaus. 
Cables are there broken in consequence of 
their burial beneath such slides. The cause 
of the movement is ascribed to the accumu- 
lation of land-worn detritus. In Japan a 
large number of earthquakes come from the 
deep sea off the mouth of the Tonegawa, 
the largest of Japanese rivers, which crosses 
an alluvial plain in its lower course. Many 
other shocks on those islands have similar 
