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THE GEOLOGICAL SOCIETY OF LONDON. 



Vol. IV. Part IIL 1844-5. No. 102. 



November 6, 1844. 

 The following communication was read : — 



Observations on the Geology of some parts of Tuscany. By 

 W. J. Hamilton, Esq. M.P., Sec. G. S. 



One of the principal physical features of the district under con- 

 sideration in the present memoir, is the existence of three distinct 

 mountain ridges, extending from N.W. by N. to S.E. by S,, and 

 parallel to the direction of the main chain of the Apennines. All 

 these ranges belong to the Scaglia, a representative of the cretaceous 

 series which is known to prevail extensively throughout Greece, the 

 Morea, the Ionian Islands, Asia Minor, and the South of France, 



I cannot pretend to define the limits of these different ranges, or 

 even to point out their exact number and geological contents, 

 having only been able to visit a small portion of them ; but the 

 following are the principal lines occurring in the district which 

 came under my consideration. 



1st. The first line, commencing between Pistoja and Prato, 

 passes through Castello and Fiesoli, and keeping to the N.E. of 

 Florence, descends in a S. E. direction to Arezzo. Castiglion 

 Fiorentino, Coz'tona, &c., when it passes to the N. E. of the Lake of 

 Thrasymene. 



VOL. IV. PART III. M M 



