vt Read Ay had 7 oe see. Le 
Mesozoic and Cenozoic Geology and Paleontology. 189 
stone on the top of the terrace; and at this place, the surfaces 200 feet 
lower, and 100 feet higher, are scored in like manner, What agency 
could produce this effect ? Here is an abrupt elevation of 100 feet 
above the striated surface; and it seems hardly possible that an island 
of ice, loaded with granite bowlders, could have stranded upon this pro- 
jecting shelf, and produced the scoring, and that, at the same time, 
others above and below could be made in like manner. 
The fourth district, in its greatest elevation ofabout 2,000 feet above 
tide water, descends to the level of Lake Ontario, 240 feet above tide, 
' for the most part, ina series of steps or terraces over the successive 
formations; the surfaces of these, frum the highest to the lowest, are 
grooved and striated, and in the limestones often beautifully polished. 
There is no high land on the north, from which glaciers could origin- 
ate to cover this entire surface. The relative levels, as well as the 
directions of the water courses, must also have been different, to have 
allowed of such effects from glaciers; for, under present circumstances, 
we should hardly expect to find a glacier advancing from the valley of 
Lake Ontario, toward the southern margin of the State, and ascending 
nearly 2,000 feet in 100 miles. Even admitting the glacial theory to - 
be true, it is probable that the glaciers would originate among the 
mountains of Canada, or farther north among the primary rocks; and 
in this event, we might expect to meet, intermingled with the earliest 
drift, a considerable proportion of granite and other pebbles and 
bowlders of the older rocks, which is not the case. 
There is another fact worthy of notice. The vertical faces of joints, 
when much separated and nearly coinciding with the direction of these 
grooves, are polished in the same manner as the surfaces. Thechinks 
and fissures, in the harder rocks along the sea shore, are polished, in 
like manner, by the washing in of sand and pebbles by the advancing 
and retiring waves. 
The first plateau above Lake Ontario is often plentifully covered 
with bowlders. These usually lie upon the surface, and always upon 
the top of the drift. They are not evenly distributed, but often appear 
in immense numbers, scattered over several acres; while beyond this, 
for a great distance, few are to be found. There appears to be no law 
regulating their distribution, though they are more abundant in the 
eastern than in the western part of the district. The bowlders are 
often in immense numbers on the low ground just north of the Ridge 
road from Wayne county to the Niagara river, and appear as if they 
had been brought there while the water was limited by this barrier, 
