154 QUATERNARY PERIOD. 



change was effected by an accumulation of masses of gravel 

 covering the lignites. 



All the above-mentioned lignites belong to the basin of the 

 Limmat and the Lake of Zurich ; but the deposit of Morschweil 

 (564 metres, or nearly 617 yards, above the sea) between St. 

 Gall and Rohrschach belongs to the basin of the Lake of Con- 

 stance. Its average thickness is about 2 feet. It furnishes an- 

 nually about 50,000 hundredweight of coal. Above and below 

 it are beds of rolled erratic blocks. In the Hiittenweid, in the 

 commune of Morschweil, the following strata are distinguish- 

 able, in descending order, according to Prof. Deicke * : 



1. 10 feet of loam. - 



2. 16 feet of erratic stones, not striated or polished. Among 



them are boulders weighing 10 hundredweight. 



3. 8 feet of loam with lignite, in which the trunks of trees 



are upright. 



4. 13 feet of erratic stones with small boulders, not exceeding 



1 foot in diameter. 



5. 6 feet of ash-grey loam, with scattered fragments of lignite. 



6. 17 feet of small erratic pebbles, among which there are 



boulders about 1 foot in diameter. 



Nearly the same succession of beds occurs in the Kropfel ; but 

 the lignite-bed, which is 3 feet thick, lies 70 feet below the sur- 

 face; and 15 feet lower down a second, thinner deposit makes 

 its appearance. 



In the Brunnenweis, which lies to the eastward, the shaft shows 

 the following strata in descending order : 



1. 21 feet of sand, with large boulders. 



2. 16 feet of ash-grey loam, with lignite, in which there are 



trunks of trees, 6 feet long and 3 feet broad, standing 

 upright. 



3. 3 feet of gravel, with small rolled pebbles. 



4. Fine sand. 



* See " Nachtrage liber die Quartargebilde zwischen den Alpen und dem 

 Jura," by Prof. J. C. Deicke, in 'Bericht der St.-Gallischen Gesellschaft/ 

 1861. 



