488 Dr. M. Ogilvie Gordon — The Langhofl T/irusf-mass. 



portion having been overlapped by another and more anterior body- 

 segment ; this is succeeded by a band covered by scale-markings (<r), 

 about six rows deep, and next these follows the posterior crenulated 

 border (b). (The specimens are numbered 2910 and 2911.) The first of 

 these shows a piece of a body-segment, 75 mm. long by 40 mm. deep ; 

 only 20 mm. of the margin is preserved. There is a trace of another 

 segment which underlies the above, also showing scale-markings and 

 a small part of the scalloped margin. No. 2911 measures 60 mm. in 

 length, by 40 in depth ; 50 mm. of the posterior crenulated margin is 

 preserved. 



Like the remains of the Merostomata from British and Irish 

 localities, those from Brazil and the Cape are also associated with 

 plant-remains, and may have been of lacustrine origin. It is highly 

 probable that, although based onlj' upon fragmentary remains, 

 Sastimima includes specimens of more than one species, if not of 

 more than one genus. It is not my intention, however, to suggest 

 fresh names for these fragmentary Arthropods ; but their presence in 

 such widely separated localities is a matter of extreme interest, and 

 may prove useful as a means of marking synchronous or homotaxial 

 horizons over very large areas. Similar fragments (see woodcut, Fig. 1) 

 were observed by the late Mr. W. H. Baily in the Devonian rocks of 

 Kiltorcan, as well as those already referred to in the Upper Ludlow 

 of Shropshire. 



IV. — Note on the Langkofl THUUsT-itAss. 

 By Mrs. Maria M. Ogilvie Gordox, D.Sc, Ph.D., F.L.S. 



IT will be remembered that two years ago, in 1907, I pointed out 

 the occurrence of important planes of overthrust at the base of the 

 Dolomite Mountain-massive of Langkofl. and Plattkofl in South Tyrol, 

 which explained its apparent ' reef -like ' form, and its curious position 

 above "Wengen lavas in some places and Muschelkalk at others. 

 I showed that at Langkofl. the Upper Werfen Strata and Muschelkalk 

 form a shear-slice above which the Schlern Dolomite rocks of the 

 Langkofl Mountain have been overthrust, and below which the 

 Wengen lavas and tuffs of the Ciampinoi meadowland are present; 

 also that the planes above and below this shear-slice are crush-planes 

 of extremely low inclination. 



Last autumn I continued my researches in this district, but un- 

 fortunately, owing to the pressure of other business, it is only now 

 that I have had an opportunity of preparing my work for publication. 



In mapping the Ciampinoi and Wolkenstein "hill area that descends 

 from Langkofl to Griiden Valley, I traced an important thrust-plane 

 northward across the Groden Valley to the Sorasass Alpe and Pitsch- 

 Berg on the north side. Disturbed strata are present in the Ciampinoi 

 and Wolkenstein hill area, belonging to the Wengen, Buchenstein, 

 Muschelkalk, and Werfen horizons, and they continue the same 

 E.N.E. - W.S.W. strike as the thrust -band below the Langkofl. 

 They are overthrust above the Wengen lavas and tuffs of the 

 valley segment. Where the fault-plane is exposed on the western 

 slope of the Ciampinoi hill it strikes N. 10 E. and dips ca. 20 E., 



