114 Mr Lyell on the Loamy Deposit of the Rhine. 



die of the crater is a farm-house, where a well was sunk in July 

 1833: at that time I visited the spot in company with Mr Hor- 

 ner, and we found, to our great surprise, that the materials 

 passed through were loess, covered by a small bed of cinders and 

 cindery loam. The mass of pure loess was Q5 feet in thickness. 

 How much deeper it extended was not ascertained. We did 

 not find any shells, but we were only able to examine a small 

 quantity of loess which had been taken from the well. The 

 usual calcareous concretions were in abundance. Whether the 

 overlying cinders were alluvial or showered down from the air 

 during the eruption of some vent in the adjoining country, I 

 cannot pretend to decide. No eruption, however, can have 

 taken place from the Roderberg, since the hollow of the crater 

 became, in great part, filled up with a dense deposit of loess. 



I was much strengthened by what I saw on this spot, in my 

 former opinion respecting the posteriority of the loess to the 

 more modern volcanic eruptions of the Eifel ; yet I found my- 

 self obliged, on revisiting Andernach, to admit that there had 

 been near that place some considerable falls of pumice, scoriae, 

 and volcanic sand, both during the period when the loess was 

 forming, and since its formation. I am aware how easily pu- 

 mice and other light volcanic matters may be drifted during 

 heavy rains, and that the waters capable of depositing the loess 

 might easily have washed away such transportable matter, had 

 any of it been already strewed over the land before the loess was 

 formed. In that case some alternations of volcanic cinders and 

 loess might undoubtedly have been caused, even though all vol- 

 canic eruptions had ceased before the deposition of loess began. 

 With due regard to these views, I compared with attention the 

 appearances near Andernach with those which I had seen in the 

 neighbourhood of active volcanoes, and concluded, contrary to 

 my original idea, that some volcanoes must have been in activity 

 while the formation of loess was still going on. In the hollow 

 way called the Kirchweg, immediately above Andernach, the 

 loess, having its usual characters, is still seen, with here and there 

 an included fragment of pumice, or a small quartzy pebble. I 

 collected several shells from it, and Mr Steininger gave me a list 

 of species which he procured from the spot. The thickness of 

 the loess in this and other adjoining places (as in the high road 



