392 Professor Sedgwick and Mr. Murchison on the 



Returning to our former line of section along the right bank of the Mur, 

 between the bridge of Strass and Mureck, we find some slight undulations of 

 the strata ; but on the whole the beds are so nearly horizontal,, that the same 

 groups of variously coloured^ sandy, and unctuous marls continue till the river 

 passes the latter place. Below Mureck a very fine section through the unctu- 

 ous marls exposes irregular, subordinate bands of a white, concretionary lime- 

 stone, one range of which is about eight feet thick. The rock is soft in the 

 quarry, but hardens on exposure, and is extracted in large lumps, the outside 

 of which exhibits an earthy texture. The interior is very difficult of fracture, 

 and is made up of a number of small tubular and concentric layers, which at 

 first sight give the rock a pisolitic appearance. Some of the harder masses 

 are traversed by beautiful, contemporaneous veins of crystalline carbonate of 

 lime. The beds in this section dip east at an angle of 6° or 8°. 



In the calcareous beds alternating with the various inferior groups, we con- 

 stantly remarked a tendency to concretionary structure ; and in the marls in 

 the upper part of the Sausal-hills, and of Santa Egida, we frequently found 

 balls three or four inches in diameter, made up of a congeries of spheres like 

 clusters of small grapes, which reminded us of some varieties of the magnesian 

 limestone of England. On breaking these balls the spheres were occasionally 

 hollow, but presented, here and there, obscure traces of organic structure. 



5. Arenaceous marl and sandstone ; concretionary beds of calc.grit and oolitic limestone ; 

 micaceous, yellow sand, and small beds of pebbles, &c. 



The white marls and concretionary limestone of Mureck, are succeeded on 

 the line of dip by a great, complex deposit forming the highest group of the 

 whole section. The lower members of this group consist of arenaceous, dark- 

 coloured marl alternating with calcareous sandstone, which, opposite to Sixt- 

 Miihle and at other places on the banks of the Mur, contain fossils, of which 

 we may mention the following genera : Cerithium, Modiola, Pecten, and 

 Cardium. From Sixt-Miihle to Radkersberg, the whole system becomes more 

 arenaceous ; and at the latter place, where the hills terminate towards the 

 plains of Hungary, the cliff which overhangs the Mur exhibits a good section 

 in the following ascending order. 



° Ft. In. 



a. Fine, incoherent, calcareous, grey and blue, micaceous sands and marls, 

 with a great profusion of small Cerithia, of which the most common spe- 

 cies very closely resembles the recent species C. vulgatum. Associated with 

 it is"the Corbula complanata ? (Sowerby *), a minute Natica, a Nerita, 

 &c. These beds are so disintegrated that their exact subdivisions cannot 

 bedetermined. Their total thickness from the base of the cliflF is about 

 60 or 70 feet 70 



* Min. Con. Tab. ccclxii. fig. 7 & 8. 



