58 
GILBERT MEETING 
the Ice Age. Inclination was now towards the incidental sugges¬ 
tion of Professor Davis early made that an orogenic explanation 
should be carefully examined. 
In the explanation of the old lake’s genesis orogeny which 
abounded in utmost profusion all about had no part. It was 
too evident that it was at this late date hard to realize that the 
great body of inland waters of which the Great Salt Lake of 
today was an all but vanquished vestige might not have been after 
all an anomaly among desert features; or that it might represent 
merely a special phase of a through-flowing stream which was 
not quite large enough to negotiate the orogenic barrier which 
chanced to arise athwart its path, while its companion and paral¬ 
lel stream, the Green River, re-enforced by the Grand and other 
eastern tributaries, was sufficiently powerful to hold its own 
against all vicissitudes and to carve out through the rapidly 
bulging Colorado Dome a Titan among chasms. Blocked by such 
a formidable rampart, the old antiquated river spread out far and 
wide over the adjoining intermontane plains, until, finally, robbed 
of its headwaters through diversion by lava flows, it could no 
longer furnish the lake with its chief supplies, when disiccation 
set in with marvelous rapidity. 
When I remarked that these factors did not matter much and 
that the great service of his Lake monograph still remained un¬ 
impaired he was visibly touched and naively expressed deep ap¬ 
preciation that we should think so. 
On the Basin Range structures Gilbert’s thought seemed con¬ 
stantly to dwell; and he returned to the topic again and again. 
The theme appeared to greatly trouble him. He expressed desire 
to review his early hypotheses from the foundations up. He 
manifestly was in the very midst of it then. When on the gallop¬ 
ing Wheeler military jaunts which were so little adapted to close 
geological observation, the theory originally flashed across his 
mind, as a meteor flashes athwart the sky. And like the meteor’s 
basic message on its composition and its orbit the fault-block 
hypothesis was an impression, and its fundamental elements al¬ 
ways remained undetermined. 
The conception that the Basin Ranges were tilted fault-blocks, 
floated on the liquid interior of the globe, and tumbled about 
much like ice-cakes in a river at the time of the Spring break-up. 
