Notice of Active and Extinct Volcanos. 243 



stone containing trilobites and other petrifactions, which stamp 

 it as belonging to the transition series. 



" These rocks in a few places support horizontal beds of what 

 appears to be the second or variegated sandstone formation. 

 Scattered however over the greater part of the district alluded 

 to, are a number of little conical eminences, often with craters, 

 the bottoms of which are usually sunk much below the present 

 level, and have thereby in many cases received the drainage 

 of the surrounding country, thus forming a series of lakes, 

 known bv the name of " Maars," which are remarkably distin- 

 guished from those elsewhere seen by their circular form, and by 

 the absence of any apparent outlet for their waters. 



" Steininger, a geologist of Treves, who has published the most 

 circumstantial account of this district that has yet appeared, dis- 

 tinguishes these craters into three classes. 



" The first includes those properly speaking known by the name 

 of " Maars,"— volcanos which have ejected nothing but loose 

 fragments of rock with sand and balls of scoriform lava. In this 

 class are : — 



1. The Lake of Laach. 



2. The Maar of Ulmen. 



3. Three Maars at Daun. 



4. Two at Gillenfield. 



5. One at Bettenfield. 



6. One at Dochweiler. 

 7- One at Walsdorf. 



8. One at Masburck, 

 No. 6 and 7, however, have fallen in. 

 " The second class is distinguished from the preceding in consist 

 ting of those which have ejected fragments of slag, sometimes 

 loose, and sometimes cemented together into a paste. Of this de- 

 aomination are : — 



1. Three Craters at Gillenfield. 



2. Two at Bettenfield. 



3. One at Gerolstein. 



4. One at Steffler. 



5. Two at Boos. 



6. One at Rolandseck. 



"The third class includes such volcanos as have given out 

 streams of lava as well as ejections of loose substances. Of these 

 latter we may mention : — 



2. Two at Bertrich (one very small.) 



3. One at Bettenfield (the Mosenburg.) 



4. One at Ittersdorf. 



5. One at Gerolstein. 



6. One at Ettringen. 



