408 Dr. MW. Ogilvie Gordon—Overthrust Structure in Dolomites. 
V.—Pretiminary Note on Ovrerrurust Structure at LANGKOFL IN 
THE DOLOMITES. 
By Dr. Marra M. Ocityiz Gorpon. 
EOLOGISTS who are familiar with the Dolomites of South Tyrol 
will know the transverse sections of Langkofi and Plattkofl 
Dolomite given by Geh. von Mojsisovies (‘‘ Dolomit-Riffe,”’ 1879, 
pp. 191-204). Mojsisovics describes the Schlern Dolomite of Langkofl 
as resting conformably upon south-dipping Lower Muschelkalk and 
Werfen strata, and concludes that the Schlern Dolomite here represents 
a dolomitic facies of all the Mid-Triassic geological horizons—viz., the 
Mendola, Buchenstein, Wengen. and Cassian horizons. The Lower 
Muschelkalk and Werfen strata then bend northward with a steep 
flexure and, according to Mojsisovics, conformably underlie the same 
Mid-Triassic series of Mendola, Buchenstein, Wengen, and Cassian 
horizons, but the Buchenstein horizon is here present in the nodular 
limestone facies, and the Wengen and Cassian horizons in their 
tufaceous facies. 
In a paper which, I hope, may shortly be published, I have 
described the presence of two important thrust-planes, inclined south- 
ward, in the north wall of Langkofi and the adjacent hill-slopes on 
the north. One of these thrust-planes passes between the Schlern 
Dolomite of Langkofl and the group of Lower Muschelkalk and 
Werfen strata at its base. The Schlern Dolomite above the thrust- 
plane dips northward, the underthrust strata dip southward—rather 
more steeply than the thrust-plane which at the north wall has an 
average inclination of 15°-25° south-south-east. 
The other thrust-plane is also inclined south-south-east and passes 
between the Werfen and Muschelkalk strata of the underthrust group 
and the Wengen lavas on the hill slopes adjacent to Langkofl on the 
north. For convenience, I have termed the segment of older Trias 
at the base of Langkofl the ‘ Montesora’ segment. 
Another thrust --plane inclined southward is present in the 
Plattkofl or south aspect of the Langkofl and Plattkofl group. The 
tufaceous and Cipit Limestone facies of Cassian strata in Fassa Joch 
dovetails towards the north with the dolomitic facies of the Cassian 
horizons in Plattkofl mountain. And a thrust-plane has carried the 
southern facies northward to some extent above the dolomitic facies. 
I have farther shown that leading east-west eruptive fissures present 
on the north and south of the Langkofl and Plattkofl group in Mid- 
Triassic time were at that time undergoing depression relative to 
the intervening plateau upon which the calcareo-dolomitic deposits 
accumulated, and that simultaneously with the Mid-Triassic differential 
movements and eruptive invasions at east-west fractures a series of 
N.E.-S.W. flexures was in course of formation, the eruptive facies 
gaining ingress more especially in the troughs of that series. 
My investigation of the Bufaure group of igneous mountains 
between Fassa and Contrin Valleys leads me to conclude that this 
was a depressed series of flexures in the course of both the east- 
west and N.K.—S.W. systems of plication, and was already broken in 
Mid-Triassic time by an intersecting network of fractures. ‘The 
