alled out many
ponderous monographs in German and French by such men as Heim, Schardt,
Lugeon, Rothpletz, and Bertrand. This example, which was first (1870)
called the Glarner Double Fold by Escher and Heim, is now universally
called a nearly flat-lying "thrust fault," in accordance with the
explanations since adopted of similar phenomena elsewhere. Without
obtruding unnecessary technicalities upon my non-professional readers, I
may quote the words of Albert Heim as to the conditions as now
recognized in these parts:

"These flat-lying faults, of which those at Glarus were the first to be
discovered, _are a universal_ _phenomenon_ in the Northern and Central
Alps."[41]

[Footnote 41: "Der Bau der Schweizeralpen," p. 17.]

The favorite method of explaining these conditions has slightly changed
within recent years, as already remarked. For whereas the classic
example at Glarus was at first spoken of as a double fold-in from both
sides toward the Sernf Valley, this is now universally spoken of as a
"thrust fault," with the rocks all pushed one way. Incidentally it may
be noted that this very fact that what was long regarded as two
completely overturned folds is now spoken of as one flat-lying thrust
fault, is _prima facie_ evidence that there is here _no physical proof_
of any real overturning of the strata, such as we do find on a very
small scale in true folded rocks. The latter can usually be measured in
yards, feet, or inches; while in this example at Glarus the area
involved would be measured in many miles, and in some very similar
examples to be presently mentioned from America the measurement could
best be made in degrees of latitude and longitude or in arcs of the
earth's circumference. In these larger examples it is manifestly
impossible that there should be any physical evidence sufficient to
indicate a huge earth movement of this character, especially when, as is
usually the case, both the upper and the lower strata are _quite
uninjured in appearance_. No; the fossils are here in the wrong order,
that is all. And so, to save the long established doctrines of a very
definite order of successive life-forms, this theory of a "thrust fault"
is offered as the best available explanation. As Dr. Albert Heim himself
once expressed it very naively in a letter to the present writer, that
the strata over these large areas are in a position manifestly at direct
disagreement with the received order of the fossils, "is a f