24 SILICIFIED SHELLS AND CORAL. [CHAP. XXI. 



of beds of yellow and red clay, with accompanying- sands of ter 

 tiary formation, and, at the depth of forty feet, I observed a large 

 fossil tree converted into lignite, the concentric rings of annual 

 growth being visible. Receding from the granitic rocks, six or 

 eight miles still farther to the southeast, I found at Brown Mount 

 ain, a bluff on the Ocmulgee River, and at other places in the 

 neighborhood, a great many siliceous casts of fossil shells and 

 corals, and among others a large nautilus, the whole indicating 

 that these beds of cherty sandstone and impure limestone belong 

 to the Eocene period. 



As there is much kaolin in this series of chert and burr-stone 

 strata, I have little doubt that the petrifaction of fossil- wood, and 

 of shells and corals, has taken place in consequence of the decom 

 position of the imbedded felspathic rocks and crystals of felspar, 

 taking place simultaneously with the putrefaction of the organic 

 bodies. The silex, just set free from its chemical combination in 

 the felspar, would replace each organic particle as fast as it de 

 cayed or was resolved into its elements. 



From Macon I went to Milledgeville, twenty-five miles to the 

 northeast, the capital of Georgia. Instead of taking the direct 

 road, we made a detour, going the first thirty miles on the Sa 

 vannah railway, to a station called Gordon, where we found a 

 stage-coach ready to drag us through the deep sands of the pine- 

 barrens, or to jolt us over corduroy roads in the swamps. As 

 we were traversing one of the latter, at the rate of half a mile 

 an hour, I began to contrast the speed of the new railway with 

 stage-traveling. Our driver maintained that he could go as fast 

 as the cars. &quot; How do you make that out ?&quot; said I. &quot; Put a 

 locomotive,&quot; he replied, &quot; on this swamp, and. see which will get 

 on best. The most you can say is, that each kind of vehicle runs 

 fastest on its own line of road.&quot; 



We were passing some cottages on the way-side, when a group 

 of children rushed out, half of them white and half negro, shout 

 ing at the full stretch of their lungs, and making the driver fear 

 that his horses would be scared. They were not only like chil 

 dren in other parts of the world, in their love of noise and mis 

 chief, but were evidently all associating on terms of equality, and 



