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f'hief Dolomite niountains, such as the Lanj^kofl und PLittkofl Massive and 

 Sella Massive, are áreas of inthrow surrounded l»y laults, witliin wliich 

 the higher tlirust-slices Lave been preserved. 



One of tlie geological mapa f'hows four successive thrust-raasses — (1) 

 a basal tlirust-inass mainly composed of the Perniian Quartz Porphyry 

 and Groden Sandstones, the Lower Trias, and tlie "Cialcareous facies" of 

 Muschelkalk and Marmohita Limestone; (2) a thrust-mass coraprising 

 fragments of the older strata and widely exten<led exposiires of the porphy- 

 ntic hivas and tufaceous and dolomite facies of Middle Trias: (3) a thrust- 

 mass belonging to tlie same facies as (2), but mainly composed of Schlem 

 Dolomite, with varying thicknesses of the lavas and toffs below it and of 

 Upper Trias and younger horizons above it; (4) a thrust-raass mainly 

 composed of Upper Triassic Dolomite associated with infolds of younger 

 Mesozoic strata. The other geological map shows the datailed stratigraphy 

 of the Langkofl and Plattkofl Massive. This mountain has been regarded 

 as a "Coral-Eeef" of Middle Triassic age, but the supposed ''reef" peculiar- 

 ities are interpreted by Mis. Gordon upon the basis of the overthrust 

 structures typical of the whole área. The outstanding deformational feat- 

 ure of all the thrust-slices is the rapid variation in the thickness of the 

 various horizons of strata. Other features are the brecciated or nodular 

 structure of the rock-material in the crush-zones, passing into gneissose 

 and schistose structiu-e, and the cióse cleavage penetrating the rocks in 

 intersecting directions. The outward dip of the strata noticeable in the 

 chief mountain-massives is a dip participated in by the subjacent thrust- 

 masses and associated with steep flexures towards leading faults of the 

 later period of downthrowing and horizontal displacements. Mrs. Gordon 

 interprets the leading strike in the district as a curve round the noi"th, 

 west and south, and the transversal directions as N.N.W.-S.S.E., N.S., 

 and N.N.E.-S.S.W., the system being essentially an interference system 

 produced in virtue of the coalescence of plieational effects during the 

 interaction of north-south and east-west pressures 



