* 
lap fi 
‘ 
MDs 
of an age one degree anterior to the boulder clay. This case 
has been, like that at Ely, adduced as an instance of faulting; 
but we noticed sand of the same character as that at the side of 
the section, clearly continued beneath the clay. 
In the other case the boulder clay has been originally depo- 
sited upon the same sand, but has been subsequently itself 
eroded down to its very base, and the channel filled again by a 
fresh deposit of slightly different materials. 
Ground Plan of the Ely Clay-Pit. The width from N. to S. is exaggerated. 
Railway. 
akin 
(a) Lower green sand. (b) Kimmeridge clay. 
(c) Erratic clay, with boulders of granite, oolite, large fiints, &c. 
(d) Chalk. (e) Gault (?) 
(f) ‘Lower green sand. (gh) line of junction. 
Note on a Case of Prismatic Structure in Ice. 
By T. G. Bonyey, B.D., F.G.S. 
On Jan. 26, 1867, the attention of the writer was attracted, 
while walking with a friend in the Fellows’ Garden of Christ’s 
College, by the appearance of the ice on a pond. On pro- 
ceeding to examine a fragment from near the edge, he says, 
“it was about } inch thick, and was a mass of prisms with 
their axes perpendicular to the surface. The ends of these 
in one part were very irregular polygons; and the lines join- 
