Edinburgh Geological Society. 227 



Drift of Cromer; 4, the Middle Glacial sand ; and 5, the Boulder-clay, 

 The valley is hollowed out in these beds. Sewer-shafts sunk in the 

 bottom of the valley near Norwich have shown the existence of an 

 abrupt hole or narrow trough in the Chalk, having one of its sides 

 apparently almost perpendicular. This is filled up in part by a de- 

 posit of dark blue clay, full of Chalk-debris, exactly resembling the 

 Boulder-clay at a distance from Norwich, but quite different in cha- 

 racter from that occurring in the vicinity (No. 6) ; and this is over- 

 lain in part by a bed of the Middle Glacial sand (No. 4), and in part 

 by a Post-glacial gravel. The authors believed that this peculiar 

 hole or trough was excavated by glacial action after the deposition 

 of the bed No. 3, and that it belongs to the earliest part of the 

 Middle Glacial period. At Somerleyton Brick-kiln, near Lowestoft, 

 a perfectly similar bed occurs between the drift and sand (Nos. 3 

 and 4). 



Discussion. — The President inquired whether the perpendicular wall of chalk 

 shown in the section could be due to the action of a glacier, as supposed by the 

 author. 



Mr. Prestwich suggested that the depression formed in the chalk in other districts 

 by chemical action might possibly throw some light on the case. 



Mr. Evans thought it possible there might have been a valley originating in a 

 large fissure, and partly filled up with reconstructed glacial deposits. 



Prof. Eamsay was inclined to accept the solution offered by Mr. Prestwich, and 

 could not see any traces of the action of a glacier. 



Mr. Etheridge thought the phenomena might be accounted for by a fault. 



Mr. Hughes pointed out that the clay-bed was totally different from any of the 

 beds supposed to have been let down. 



Mr. Searles Wood. Jun., in reply, relied on the difference in character of this bed 

 to prove that the case was not the result either of a fault or of beds being let down 

 into a pothole. He had made a mistake in using the word " glacier " instead of 

 " iceberg." 



6. " On the Lignite Mines of Podnernuovo, near Volterra." By 

 E. J. Beor, Esq., F.G.S. 



The author states that the deposit of Lignite at Podnernuovo, 

 near Voltarre, is of lacustrine origin, and consists of two parallel 

 strata of compact coal about 2| metres (=8 feet 4 in.) in thickness, 

 separated by a thin stratum of marl, with marsh-shells. The lower 

 coal-bed lies on a bed of marl with marsh-shells, and the upper bed 

 is covered by a marine formation belonging to the Upper Miocene. 

 The lignite comes to the surface near the Alberese, where it extends 

 for a considerable distance. Some shifts occur bringing the upper 

 bed down nearly to the level of the lower one ; the inclination of the 

 bed diminishes gradually, and the intervening stratum of marl de- 

 creases in thickness, and probably at last thins out altogether. The 

 coal in the upper bed is better than that in the lower one. The 

 author remarks that this lignite deposit differs from those of the 

 neighbouring valleys in being purely of marsh origin, while they are 

 Estuarine. 



Edinburgh Geological Society. — I. Seventh meeting, March 4th. 

 Archibald Geikie, Esq., F.K.S., President in the chair. 



Death of Lady Murchison. — The President referred to the recent 

 death of Lady Murchison, an event Avhich could not pass unnoticed 

 by students of geology in Scotland. Sketching briefly some of the 



