122 Geological Society : — 



whilst about 150 feet off that rock crops out, showing a slope of the 

 Chalk-surface of 1 in 2. In the most interesting of all the wells, 

 after boring to the depth of 340 feet, the work was abandoned 

 without reaching the Chalk, the Drift in this case reaching to a 

 depth of about 140 feet below the level of the sea, though the place 

 is far inland. The Chalk crops out about 1000 feet eastward, and 

 at but little lower level, so that there is a fall of about 1 in 3 over 

 a long distance. 



At and near Wenclen the abrupt way in which Drift comes 

 on against Chalk has been seen in open sections. Two wells have 

 shown a thickness of 210 and 296 feet of Drift respectively ; and 

 as the Chalk comes to the surface, at a level certainly not lower, only 

 140 yards from the latter, the Chalk-surface must have a slope 

 of 1 in less than 1|, and this surface must rise again on the other 

 side, as the Chalk again crops out. The Drift here reaches to 

 a depth of 60 or 70 feet below the sea-level. 



At Littlebury, in the centre of the village, a boring 218 feet deep 

 has not pierced through the Drift, which reaches to 60 feet below 

 the sea-level. As in a well only 60 yards west and slightly higher, 

 the Chalk was touched at 6 feet, there must here be a fall of the 

 Chalk-surface of about 1*2 in 1. Eastward too, on the other side 

 of the valley, the Chalk rises to the surface. 



The places that have been mentioned range over a distance 

 of 6 miles. How much further the Drift-channel may go is not 

 known, neither can we say to what steepness the slope of the under- 

 ground Chalk-surface may reach ; the slopes given in each case are 

 the lowest possible. 



The author thinks that the channel has been formed by erosion 

 rather than by disturbance or dissolution of the Chalk. 



2. " On the Monian and Basal Cambrian Rocks of Shropshire." 

 By Prof. J. F. Blake, M.A., F.G.S. 



In a previous paper the author had suggested that the Longmynd 

 rocks were referable to the Upper Monian. He now finds that they 

 are divisible into two groups, of which the lower only can be thus 

 referred. 



This lower group is divisible into five parts : — 1. Dark Shales ; 

 2. Banded Series ; 3. Purple Slates ; 4. Hard Greywackes ; 5. Pale 

 Slates and Grits. These are shown to have a real dip to the west, 

 and not to be thrown into any folds. It is in these only that fossils 

 have been found. The lowest dark shales are not basal rocks, nor 

 derived from the eastern volcanic series. 



The junction of the upper group, which represents the true Cam- 

 brian, is unconformable, as shown by detailed stratigraphy. It con- 

 sists of three members, the middle one being slates which die out 

 northwards. There is neither synclinal nor anticlinal fold, but a 

 regular sequence and dip ; and pale slates follow on the west. The 

 base is brought into connexion with each division of the lower 

 series except No. 2. The conglomerates contain : — 1. Quartz ; 



