76 R. S. TARR 



both sand and gravel are encountered. No two of the wells 

 have the same sequence of layers, even though the wells are 

 close together. Samples prove that some of the layers are water- 

 washed sand and gravel, while others are unquestionably till, 

 with scratched stones. In a number of other places till is sus- 

 pected, though the evidence is not sufficient to prove it. 



In this series of coarse deposits, water is found at varying depths 

 in the different wells, and in differen: sediments. In some cases it 

 is found in a sandy clay, called "quicksand," in which there is so 

 much water, under such pressure, that the sand is forced into the 

 pipes in sufficient quantities to fill them and stop the water flow. 

 Between this extreme and that in which the water is found in 

 coarse gravel, there are several intermediate conditions. The 

 largest flow is obtained from the coarse gravels. 



Beneath the unquestioned till, and in various places beneath 

 the materials interpreted as probable till, is found a black sand 

 in which from 50 to 75 per cent, of the material is quartz, the 

 remainder being mainly dark shale fragments. In one of the 

 wells that reached bed-rock this black sand rests on the rock, 

 which was encountered at a depth of 342 feet. Neither here 

 nor in the other well that reached rock, nor, in fact, in any of 

 the wells, was any older drift encountered. All the materials 

 are such as might have been brought by the last ice advance, 

 or deposited since the ice-sheet melted away. Whether deposits 

 of earlier ice advances were never made here, or whether they 

 were all swept away by the last ice advance, is not determined 

 by the evidence. 



INTERPRETATION OF THE WELL SECTIONS. -■ 



Morabiic lozver series. — The history of the accumulation of the 

 342 feet of sediment revealed by these well-borings is in most 

 respects clear. That the bottom series of till, sand, and gravel 

 is morainic seems proved by several facts: (i) the neigbor- 

 hood of the massive moraine which rises above the delta two 

 miles south of the wells; (2) the position of the coarse materials 

 at the base of the series, from all other members of which they 

 differ decidedly; (3) the apparently irregular outline of the 



