50 



UNITED STATES. 



4th, A Stratum of black cfFensive mud, full ofosifeFs 

 and trunks of trees, the thickness of which he doefs 

 iiot menlicij. This stratum is found at Philadelphia, 

 between fourteen and eighteen feet deep,* at Rac- 

 coon in New Jersey between thirty or forty feet ; at 

 the city of Washington Mr. Vohiey saw it eighteen 

 feet deep at the house of Mr. Law, whose well it 

 spoiled : 



oth, Under all these strata is a bed of clay, bf 

 which the waters are retained. 



5. Region of river Alluvions* 



In the division of the soil of the United States, Mr, 

 Volney has followed the excelient arrangement of 

 Dr. Mitchell in the survey of the state of New York, 

 but he has omitted, without reason, an account of thfe 

 slate or schistus which is so abundant and character- 

 istic in many places, particularly in New York» 

 ■Where there is a continuation of schistus from the 

 Highlands to Fort Edward, a distance of one hundred 

 and forty miles. 



The fifth and last region, is the country that rises 

 in undulations from the ridge of the falls, to the feet 

 of the mountains of sandstone or granite. Its limit is 

 less easily traced in Georgia, where the talcky ridge 

 does not appear. This region is marked by its un- 

 dulations, consisting in some places of isolated risings^ 

 in others of ridges of little hills ; and by its soil being 

 composed of different kinds of earth and stones, in 



* It is to be understood that this rs by no means general. 



