Ch.IX.] PROOFS OF SUCCESSIVE ELEVATION. Ill 



this as in many other limestones, which, when exposed to the 

 action of frost, scale off in small fragments at right angles 

 to the plane of stratification. It might have been expected 

 that; in this case, a talus composed of a breccia of the lime- 

 stone would be found on each ledge, so that the slope would 

 become gradual, but perhaps the fragments instead of accumu- 

 lating may decompose and be washed away by the heavy rains. 



The line of some of the valleys near Lentini has evidently 

 been determined mainly by the direction of the elevatory force, 

 as there is an anticlinal dip in the strata on either side of the 

 valley. The same is, probably, the case in regard to the great 

 valley of the Anapo, which terminates at Syracuse. 



Sea-cliffs proofs of successive elevation. No decisive evi- 

 dence could be looked for in the form of the valleys to deter- 

 mine the question, whether the subterranean movements which 

 upheaved the newer Pliocene strata in Sicily were very numer- 

 ous or few in number. But we find the signs of two periods 

 of elevation in a long range of inland cliff on the east side of the 

 Val di Noto, both to the north of Syracuse, beyond Melilli, and 

 to the south beyond the town of Noto. The great limestone 

 formation before mentioned, terminates suddenly towards the 

 sea in a lofty precipice, a, b, which varies in height from five 



No. 23. 



hundred to seven hundred feet, and may remind the English 

 geologist of some of the most perpendicular escarpments 

 of our chalk and oolite. Between the base of the precipice 

 a, 6, and the sea, is a-n inferior platform, c, b, consisting of 

 similar white limestone. All the strata dip towards the sea, 



