TRANSACTIONS. 55 



derived from streams whose beds not unfrequently lie 

 above the level of the plains they traverse, and which are 

 kept from overflowing the champaign and converting it 

 into pestilential marshes only by high and costly embank- 

 ments. You are now struck with the general character- 

 istic of the physical geography of Western Italy, which 

 distinguishes it so remarkably from most other mountain- 

 ous countries. The surface is not composed of hills and 

 dales with level plateaus on the ridges and narrow threads 

 of what in America we call intervale bordering the water- 

 courses at the bottom of the valleys between, but it con- 

 sists of wide spread plains and abrupt mountain elevations, 

 with no intervening gradual rise to break the suddenness 

 of the transition. The plains are generally at but a small 

 elevation above the sea, and though in some instances 

 probably of submarine formation, yet in many others they 

 appear to owe their origin to the action of the torrents, 

 which, after the Apennines were bared of their forests, 

 gradually washed down the vegetable soil and disintegra- 

 ted or decomposed rock, first into their own estuaries, 

 and then, when these were filled to the water level, de- 

 posited it on a broader surface, until a wide and continu- 

 ous belt of champaign country was interposed between 

 the mountains and the sea. 



Eastern Tuscany, being more distant from the sea and 

 more elevated, is less strongly marked by the features^ I 

 have described; but the tendency to form extensive levels 

 and sudden ascents still characterizes its geography as it 

 does that of the Pontifical states west of the Apennines. 

 The climate of the territory of the Church is somewhat 

 Edilder than that of Tuscany, and the funeral cypress, the 

 myrtle and the laurel, all evergreens, now become frequent 

 and conspicuous ornaments of the pleasure grounds and 

 gardens. Some miles before reaching Rome, you enter the 

 famous Campagna di Roma, the fertile but pestilential 

 plain, now almost destitute of trees and rural habitations. 



