Mr Lyell on the Loamy Deposit of the Rhitie. 117 



seen in the deep gravel pits at the Manheim gate of Heidelberg, 

 where the following section is exposed. 



1. Vegetable soil with gravel. 



2. Loess without any appearance of stratification, and with 

 land and fresh-water shells. 



3. Loess and gravel in alternating layers. 



4. Sandy loess with shells. 



5. Coarse gravel and loamy sand in horizontal strata, from 

 one to two feet in thickness. 



This section shews that, after the loess with shells (No. 4.) 

 had been deposited, alternate strata of gravel and loess accumu- 

 lated to the thickness of 12 feet, and then pure loess. 



In travelling from Heidelberg to Heilbronn, by Wiesenbach 

 and Sinsheim, a country composed of the bunter-sandstein, 

 muschelkalk, and keuper of the Germans, I found the loess at 

 various heights filled with both land and fresh water or amphi- 

 bious shells, — the Succinea elongata generally equalling or sur- 

 passing in the number of individuals all the accompanying land- 

 shells. I collected 158 shells from the loess between Heidelberg 

 and Heilbronn, of which 80 belonged to Succinea minuta, 68 to 

 the genus Helix, and 10 to the genus Pupa. Heilbronn is 

 nearly 500 feet above the level of the sea, and M. Titot of 

 Heilbronn informed me, that some of the loess on the hills 

 near Heilbronn lies about 300 feet above the Neckar. If 

 this is the case, the height of the loess must sometimes be more 

 than 800 feet above the sea. Part of the district here alluded 

 to, is within a few miles of that elevated table-land above the 

 Bergstrasse between Wiesloch and Bruchsal, which I had visited 

 the year before, where the loess attains the thickness of 200 feet 

 and upwards, and contains a great variety of recent shells, many 

 of them retaining their colour. 



From Heilbronn I went to Stuttgardt, and, on the right bank 

 of the Neckar, near Canstadt, found loess containing its usual 

 fossils, overlying a deposit of tuff, travertin, and marl. This 

 fresh water formation extends for five or six miles along the 

 Neckar, by Canstadt and Miinster, and in part of it Professor 

 Jager has found the remains of a tortoise, and some plants which 

 appear to be of extinct species. 



Whether the overlying loess is connected in age with the tra- 



