236 M; Paul Savi's Considerations on the 



The third class, though deprived of all communication with 

 the sea, have a bottom of marine mud ; this origin is suffi- 

 ciently proved by the shells which it contains, and especially by 

 the Cardium edule and the leaves of algae which are found on 

 digging. In summer these marshes become dry, and saline 

 efflorescences are found on the surface. 



Marshy Lands recently improved. 



M. Savi confirms the fact previously known and described 

 by Count Fossombroni, first in his dissertation on the Val di 

 Chiana, and then in his report on the low lands {maremmcs) 

 of Tuscany, presented to the grand duke*, that marshy land, 

 dried by draining and covered with artificial soil or colmate, 

 continues to be for a long time a source of insalubrity ; the im- 

 provement takes place slowly, and requires years for comple- 

 tion ; it seems as if the healthy earth, which covers the former 

 marshy bottom, must acquire a certain degree of thickness and 

 compactness before it can replace the soil which was noxious 

 under atmospheric influence. 



The existence of common salt in these dangerous soils has 

 not escaped the notice of Count Fossombroni, who observed 

 its influence, and has described by the name of salmastraje, 

 this sort of dried lands, producing efflorescence in dry seasons. 

 These salmastraje are incapable of sustaining the greater num- 

 ber of plants which grow in good soils ; when they spread, 

 the vegetation of contiguous soils becomes languishing, and 

 is eventually destroyed. Gradually, however, fresh vegeta- 

 tion takes place, and of the only kinds which suit these soils: 

 among them occur Atriplex, Salsola, Statice, &c. 



M. Savi compares the soil of Volterra to these salmastraje, 

 as containing elements capable of undergoing modifications 

 analogous to those which are produced in the salmastraje. 



The soil consisting of mattajone, interspersed with eruptive 

 rocks, and subject to subterranean emanations, contains gyp- 

 sum, sulphur, and common salt, accompanied with sulphate 

 and carbonate of soda, &c. ; and to these must be added an 

 oleo-bituminous substance, which in hot seasons yields evi- 

 dent exhalations, and whenever fresh surfaces of the mattajone 

 are brought into contact with the air. In spite of its sterility 

 this soil exhibits some traces of vegetation, so that to the sub- 

 stances already noticed as contained in it, must be added the 

 remains of dry vegetables in a state of decomposition. These 

 lands appear therefore to resemble in many respects marshy 

 lands rendered unhealthy by rains. Water acts readily on 



* Inserted in the work of M. Ferdinand Tastini, ' On the Improvement 

 of Tuscan Low Lands.' 



