134 Mr. Ivory on the Shortest Distance 



derable hills, very unlike the elevated masses of the same age in 

 Salzburg and Bavaria. Not far from the gorge of the Tag- 

 liamento we found tertiary molasse, conglomerate, and marl, 

 dipping from the nearest precipices of Alpine limestone to- 

 wards the south ; but we could not discover the exact repre- 

 sentatives of those tertiary groups described, by one of the 

 Authors of this paper, as occupying the neighbouring district 

 between the Brenta and Piave # . Indeed these groups seem 

 to thin off gradually towards the east : and we lose all vestiges 

 of them beyond the great delta formed by the rivers Piave, 

 Tagliamento, and Isonzof. In the neighbourhood of Trieste, 

 all the mountains are composed of the younger secondary 

 strata, which in many places come down to the coast and form 

 bold promontories, standing out into the deep sea of the 

 Adriatic. 



Description of Pla te\\. 

 Fig. 1. Transverse section of the eastern Alps, from the al- 

 luvial and tertiary plains of the Friuli on the south, to 

 the valley of the Traun and the tertiary plains of 

 Salzburg on the north. 

 Fig. 2. Transverse section (parallel to Fig. 1.) from the pri- 

 mary mountains of Gastein to the tertiary plains of 

 Bavaria. 

 Fig. 3. Red sandstone, grauwacke, transition limestone, &c, 

 as seen on the banks of the rivulet below Bleiberg in 

 Carinthia. 

 Fig. 4. Position of the spathose iron ore N.W. of Leoben ; 



from a section by Prof. Rippl. 

 Fig. 5. Section of the salt deposit of Hall near Inspruck. 

 Fig. 6. Sectional plan of the salt-works of Ischel. 

 Fig. 7. Section, showing the relations of the Alpine limestone, 

 red sandstone and porphyry, between Neumarkt and 

 Cavalese in the southern Tyrol. 



XV. On the Shortest Distance between two Points on the Earth's 



Surface. By James Ivory, Esq. M. A. F.R.S. 8$c.% 

 TT may not be improper to illustrate the series in the Maga- 

 -■- zine for last month by applying it to an example ; and I 

 shall take the one given by M. Puissant, at p. 42. of the Ad- 

 ditions to the Conn, des Terns for 1832. 



* See Phil. Mag. and Annals, N.S. vol. v. p. 401. -Edit. 



f We had no opportunity of studying the interesting phenomena of 

 this delta ; but some notion may be formed, even by ours mall section (PI. II. 

 fig. 1.), of its rapid increase during the last 1400 years 



t Communicated by the Author* 



+ The 



