U4 NOTES AND ILLUSTRATIONS. 



formerly united. The Caspian Sea is three hundred leagues long, and fifty broad. Lake 

 Aral about one hundred leagues long, and fifty broad ; the latter is about one hundred 

 leagues east of the former; the intervening country is a sandy desert; neither have an 

 outlet ; both are salt, and the surplus waters are carried off by evaporation. The Caspian 

 receives no rivers from the east, and Lake Aral none from the west. From these cir- 

 cumstances it is inferred that they were formerly united. 



Since the cultivation of our country great changes have taken place in rivers, streams, 

 and small lakes. Some that were formerly full of water are nearly dry, and others are 

 entirely so. These changes will proceed, and they may be ascribed to the following 

 causes : 



1. The cutting down of the woods, and the draining of swamps, expose the waters to 

 the power of the sun, and dry up the sources from whence they proceed. 



2. Cultivation increases the alluvions of rivers, &c. by loosening the soil, and de- 

 priving it of the trees and plants which prevented it from being carried off by the water 



NOTE H. 



The fossil shells and petrifactions which have been discovered all over the world, on 

 the loftiest mountains as well as in the bowels of the earth, are justly considered as the 

 most interesting phenomena of nature. Linnaeus says, that " the innumerable petrifac- 

 tions of foreign animals, and of animals never seen by any mortal in our day, which often 

 lie hid among stones under the most lofty mountains, are the only remaining fragments of 

 the ancient world." Buffon denominates them the monuments, and Pallas styles them the 

 medals, of nature. Dr. Barton has expressed this idea in the following impressive Ian-,, 

 guage: "I consider the petrifactions and impressions which are found on many of our 

 mountains, as some of the most interesting medals of the revolutions which our country 

 has undergone." 



This country furnishes these medals of nature in as great variety and abundance as 

 any in the world. They are found in a number of forms; 1. The fossil shell detached 

 from any other substance; 2. The real shell embedded in, or adhering to, stone; 3. The 

 impressions on stone of the elevated and concave surfaces of the shells, without aoy ves- 

 tige of them. 



Kalm made many interesting discoveries of petrifactions in the northern parts of 

 this state. On the mountains at Crown Point, he found petrifactions of all kinds, 

 and chiefly pectinites, or petrified ostrea pectines ; and sometimes whole strata of the 



