THE CAMP-MEETIXG CUTTING. 689 



together, and iniinediutelv above it the newer ohiy or f^and is wholly nndis- 

 turbed to the surface of the terrace. Also, in many masses of the laminated 

 clays a beautiful pressui-e cleavage has been developed, a series of fine, 

 closely approximated slip faults making a large angle with tlie lamination, 

 and dipping sharply northward in the direction toward which the pressm-e 

 came. The section shown in PI. XVII (p. G92), taken from a similar 

 localitv, might have been many times exactly duplicated in the first oOO 

 feet south of the brook. 



I assume this work to have been done by the advance of a glacier into 

 the water, and not by icebergs, because only a single great body of ice 

 moving over the soft mass of clays could have planed them down to so true 

 a level except when the protuberance of the di'umlin caused an in-egulai'ity 

 in its action, and the great disturbance of the clay and subjacent sands for 

 a deptli of above 20 feet over so large a space would indicate a mass of 

 very considerable thickness which was pushed over the surface and not 

 simply carried forward by the current. Except for these reasons, I do not 

 see why a continuous mass of floe ice might not have done the work, for 

 the scratched bowlders in the till layer seem to have been derived from the 

 earlier till of the drumlin. 



The upper sands and days. — Above the line of disturbance a heavy 

 layer of coarse sands, grading southwardly into laminated clays, smoothes 

 over the irregularities of this surface and builds up the terrace to its 

 completion. Commencing at the north end, the sands dip sharply south- 

 ward and represent plainly an advancing delta front or growing sand 

 bank, the sands ha^dng• been pushed over its surface and deposited upon 

 its southern slope. 



In the central portion, over the more irregular surface of the fourth till, 

 these sands — which, where the till ends abruptly, I have already described 

 as deposited continuously against the southern termination of the latter, and 

 as thus being continuous with the sands below the till — are carried on in 

 broad, more nearly horizontal sheets, with finely developed flow-and-ph;nge 

 structure. 



Southward, beyond the brook ravine, these horizontal sands are capped 

 by a thick upper layer of cross-bedded sands which dips sharply south and 

 which pi'obably represents the further advance of the delta or bank froin 

 the north, the intermediate connecting portion having been removed by 



MON XXIX 44 



