M. Ogikie Gordon — Fauna of Upper Cassian, South Tyrol. 3i3 



Horizon a (von "Wohr.). 



Augite porphjTy 

 and tuffs. 



So 



« 3 



^02 



I 



' Cipit Limestones ' and volcanic tuffs ; 

 tufaceous marls, impure limestones, 

 lignite, and aragonite. Spiroslylus 

 subcolumnaris, Ptychostoma i^Uuroto- 

 moides, Neritopsit decussata, armata, 

 Astartopis Richthofeni, and crowded 

 fragments of species of Solen^ Flicatula, 

 Placiuiopsis, Avicula, etc. 



Pale-greenish tufaceous shales, reddish- 

 brown tufaceous breccias with quartz 

 grains, glassy and metalliferous ore 

 inclusions, limestones with uneven 

 bedding surfaces. These are the chief 

 horizons of Upper Cassian bivalves : 

 Avicula Cortinensis, Tofanm, Sturi, 

 Cassiana ; Cassianella decussata ; 

 GerviUia Ogilvice, angulata ; Myo- 

 phoria decussata ; Hoernesia Johannis 

 Austrim ; Lima angulata ; Pecten 

 Landranus, tubulifer ; Trigonodus 

 Rablcnsis ; etc. 



Irregular crags and blocks of ' Cipit 

 Limestones ' in tuffs. 



Dark tufaceous earth and marls ; thin- 

 bedded shales and limestones containing 

 rich fauna of small forms, in t}'pical 

 ' Stuores ' character : Cardita cretiata, 

 Koninckina Leonhardti, Trachyceras 

 Aon, Nucula lineata, strigilata, 

 Schizogonium subcostatum, etc. 



Gypsiferous marls, aragonite, tufaceous 

 grits and shales with ' Cipit Lime- 

 stones ' ; sponges, corals, echinoderms, 

 Fosidonomya Wengensis, etc. 



Ashy and felsitic series, black tufaceous 

 earth, occasional dark bituminous 

 limestones : Halobia Lommeli, Posido- 

 nomya Wengensis, plants, etc. (for 

 Stuores-Cassian and "Wengen Series, 

 of. aut., 1893, p. 16). 



The Lower and Middle Cassian horizons, distinguished by me in 

 1893, are here combined as one palEeontological zone, tlie Lower or 

 Stuores-Cassian zone; since, although the subdivision is useful in 

 field survey, the horizons are not palasontologically independent. 



The stratigraphy of the Upper Cassian zone in Enneberg and 

 Ampezzo is more difficult than the palaeontology, since the lower 

 Raibl fossiliferous sandstones are replaced by various local facies, 

 wholly dolomitic (as at Lagazuoi), or developed as a series of 

 dolomitic limestones and irregular banks of dolomite, interbedded 

 with marls and sandstones (as at Roces Alpe). 



In Falzarego Valley the Upper Cassian tufaceous series rests 

 conformably upon Cassian strata containing the typical Stuores 

 fauna, and is succeeded by a bed of dolomite of varying thickness, in 

 some places fossiliferous, with Gastropod colonies, coral banks, alg^, 

 etc., in others unfossiliferous and interlayered with volcanic sand 



