106 BANKS OF FOSSIL SHELLS. [CHAP. XXVI. 



On our way back to the town, at places a mile 

 and a half from the sea, I examined some large banks 

 of fossil shells of the Gnathodon, lying as if they had 

 been washed up by the waves at a time when the 

 coast-line extended only thus far south. I also found 

 that the city of Mobile itself was built upon a similar 

 bed of shells, in which no specimens of the Neritina 

 occurred ; but I was told by Mr. Hale, that he has 

 met with them in banks much farther in the interior, 

 and, as he truly remarked, they refute the theory 

 which would refer such accumulations to the Indians, 

 who, it is well known, were accustomed to feed on 

 the Gnathodon. The distinct stratification seen in 

 some of the heaps of shells and sand at Mobile, also 

 satisfied me that they were thrown up by the action 

 of water. Mr. Hale gave me a map, in which he 

 had laid down the localities of these beds of fossil 

 Gnathodon,, some of which he has traced as far as 

 twenty miles into the interior, the accumulations in 

 creasing in thickness in the most elevated and inland 



O 



situations, and containing there an intermixture of 

 the Neritince with the Cyrena, which last seems only 

 to occur in the recent banks of mud and sand. Mr. 

 Hale observes, &quot; that the inland heaps of shells often 

 rise so far above the level of the highest tides, that 

 it seems difficult to account for their position simply 

 by the advance of the delta, and without supposing 

 that there has been a slight upheaval of the land.&quot; 



In the gardens at Mobile, there were jonquils and 

 snowdrops in flower, and, for the first time, we saw 

 that beautiful evergreen, the yellow jessamine (Gel- 

 semium sempervirens), in full bloom, trailed along the 



