CHAP. XVII.] ALLIGATORS. 237 



mouth of the Altamaha river, in proof of a former subsidence ; 

 but a stranger is in great danger of being deceived, because the 

 common pine, called the loblolly (Pinus tceda), has tap-roots as 

 large as the trunk, which run down vertically for seven or eight 

 feet, without any sensible diminution in size. At the depth of 

 about ten feet below the surface this root sends off numerous 

 smaller ones horizontally, and when the sea has advanced and 

 swept away the enveloping sand from such tap-roots, they remain 

 erect, and become covered with barnacles and oysters. When so 

 circumstanced, they have exactly the appearance of a submarine 

 forest, caused by the sinking down of land. A geologist, who is 

 on his guard against being deceived by the undermining of a cliff, 

 and the consequent sliding down and submergence of land covered 

 with trees which remain vertical, may yet be misled by finding 

 these large tap-roots standing upright under water. 



As the alligators are very abundant in the swamps near the 

 mouth of the Savannah, I heard much of their habits, and was 

 surprised to learn that pebbles are often met with in their stom 

 achs, which they have swallowed to aid their digestion, as birds 

 eat sand and gravel to assist the mechanical action of the gizzard. 

 The peculiar conformation of the alligator s stomach confirms 

 this view. On the site of some of the old Indian villages whole 

 baskets full of flint arrow-heads have been picked up, and some 

 of these, much worn and rubbed, have been taken out of the 

 stomachs of these reptiles. 



The extraordinary tenacity of life manifested by the alligator 

 when seriously mutilated, led Dr. Le Conte to make a series of 

 experiments, with a view of throwing light on the philosophy of 

 the nervous system in man as compared to the lower animals. 

 A young alligator was decapitated at the point where the neck 

 or atlas articulates with the occiput. Not more than two ounces 

 of blood flowed from the wound. The jaws of the detached head 

 still snapped at any thing which touched the tongue or lining 

 membrane of the mouth. After the convulsions produced by de 

 capitation had subsided, the trunk of the animal remained in a 

 state of torpor resembling profound sleep. But when pricked or 

 pinched on the sides, the creature would scratch the spot, some- 



