296 THE CANADIAN NATURALIST. [Vol. X. 



More careful examination is necessary to determine whether this 

 " boulder clay " is older or newer than the gravel which flanks 

 the hill, for in some places it appears to overlie the gravel, but it 

 may have been derived by land-slides from the higher level of the 

 steep hills. In this region, north-west of Ancaster the hills, 

 flanked with beaches, are separated by ravines, often 100 feet 

 deep, with beds not more than 240 feet above Lake Ontario. 



Terraaa at the level of 261 -224 /fc? — On the hills adjacent to 

 the beaches described, near the outlet of Glen Spencer, there is a 

 terrace with a rolling surface (on which is the Roman Catholic 

 cemetery) of sandy material, having a height of 261 feet above 

 the lake. The side of the same hill, at a height of 224 feet, shows 

 stratified sand and fine gravel, which is exposed for fifty or sixty 

 feet almost vertically. This is on the northern side of the town 

 about three-fourths of a mile eastward of the railway station. 

 The sand contains layers of fine gravel, much of which is evi- 

 dently of the Hudson river formation. 



Terrace at a Level of ISO/ecY. — One of the most perfect of 

 the '' sheep's back " occurs on the southern side of Dun das, with- 

 in the corporation. This is situated behind "Gartshores dam" 

 and has a height of 180 feet (levelled). A gravel pit has been 

 opened on the upper portion and stratified gravel has been ex- 

 posed for a depth of 30 feet. The lower portion of the hill near 

 the dam is composed of blue clay, but a section of the whole hill 

 has not been laid open. Most of the gravel is fine, but it contains 

 a considerable number of stones eight or ten inches in diameter, 

 with a few slabs as much as one and a half feet in diameter. 

 These larger stones are mostly composed of Niagara dolomites 

 and are semi-ano'ular. T did not find Hudson river fossils in the 

 pebbles, but am of the opinion th;it much of the gravel is com- 

 posed of these rocks. 



The Great Terrace at 116 feet above Lake Oi\tario is the 

 most widely spread of all the ancient beaches. At the Dundas 

 valley it occurs on the northern side of the town and includes the 

 higher portions of the terrace on which the cemetery is situated. 

 Here the surface is composed of brown clay, underlaid by a sort 

 of quicksand, which is probably Saugeen clay. 



The terraces and beaches at about this height are seen on the 

 northern side of Burlington bay and farther eastward south of 

 the lake. The Burlington heights (108 feet) belong to this sys- 

 tem. Eastward from these heights it runs diagonally with a 



