18 GEOLOGICAL MEMOIES. 



The OongericB are among the most characteristic forms of the 

 uppermost beds of the Tertiary basins of Yienna and Hungary, these 

 being generally known amongst Austrian geologists as " Congerian 

 strata." The most important species in the neighbourhood of 

 Yienna is C. suhglohosa, Partsch ; but it seems to be confined to that 

 district. It is met with in immense numbers in a yellow loam and 

 the underljT-ng blue sandy clay (oberer Tegel), associated with ilf^Za- 

 nopsis 2£artiniana , Per., M. Bouei, Fei., Piano i^his marginatum, Dva.-^., 

 Cardium apertum , Miinst., Cardium conjungens, Partsch, Unio atavus, 

 Partsch, and several other species of brackish-water habits. These 

 strata are peculiar to the Yiennese and Hungarian basins ; and G. suh- 

 glohosa, though extremely abundant in certain localities, is very rare 

 north of the Danube, being apparently represented by other species 

 of the same genus. 



Congeria triangidaris occurs in the same division of the Yienna 

 Tertiaries as the last species, but is never associated with it, being 

 restricted chiefly to ]\Ioravia and Hungary. C. rJiomhoidea is a new 

 species, occurring only at a few localities near Fiinf kirchen, in Hun- 

 gary. C. Partscliii, Czjzek, is confined to a few localities near Yienna 

 and in the Hungarian basin, but is never associated with C. suhglohosa. 

 C. CzjzeMi, Horn., is another rare species; it occurs only in the neigh- 

 bouiiood of Oedenburg (W.Hungary), associated with G. triangularis. 

 Of the other species, G. spatulata, Partsch, is very abundant, and is 

 found with G. suhglohosa, generally inside it, while G. amygdaloides 

 and G. Basteroti occur in marine deposits, the last-named being com- 

 mon to the Tertiary basins of Yienna, Bordeaux, and Touraine. 



The genus Pinna has yielded two very large species, which occui' 

 also in the Subapennine deposits ; they are P. Broccliii, D'Orb., and 

 P. tetragona, Brocchi, and are found in the Leithakalk and the un- 

 derlying marls. 



The Malleaceae are represented by 1 species of Avicula and 3 of 

 Perna. The former is A. phalcenacea, and occurs in the deposits of 

 Grund and Gauderndorf, as well as in the Tertiary basins of Bordeaux 

 and Touraine. Perna Soldanii, a gigantic species of tropical charac- 

 ter, occui's also in the Subapennine deposits, as well as near Asti, 

 and most abundantly at the mouth of the Pvhone. P. Rollei and P. 

 radiata are new species. 



The Pectinidse occurring in the Yienna basin are 5 species of Lima, 

 1 species of Limea, 19 species of Pecten, 1 species of Hinnites, 2 spe- 

 cies of Plicatida, and 1 species of Spondylus. 



The species of Lima are generally found in the sands of Grund, 

 and closely resemble those of Touraine. One of them, L. squamosa, 

 Lam., is a recent species, which ranges from the Mediterranean to the 

 Atlantic coasts. 



The only known species of Limea, L. strigillata, Brocchi, occurs in 

 the Leithakalk and the Baden " Tegel," under the same circumstances 

 as in other localities. 



The species of Pecten have been of great assistance in fixing cer- 

 tain stratigraphical horizons in the Yienna basin. The most ancient 

 species is P, Holgeri, Geinitz, which occurs in a coarse sand resulting 



