Mesozoic and Ccvnozoic Geology and Palaeontology. 291 



pebbles of the same occur. In some places the coarser and finer 

 materials are intermingled, in the greatest confusion, and heaped up 

 into conical hills thickly scattered over the surface. And again the 

 same materials are accumulated in long hills or ridges having a deter- 

 minate direction, and sloping down from a high northern elevation to 

 the general level of the country south. 



On one hand, we have comparativel}^ an evenly distributed deposit, 

 as if made by the retiring waters of an ocean ; on the other, the long 

 hills, with certain directions, show a determinate course and more 

 powerful current in the ocean, while the irregular, conical and dome- 

 shaped hills, with deep, bowl-shaped cavities, show the force of con- 

 tending currents, or of other obsti'uctions, in the course of the trans 

 ported materials. 



The great bulk of the deposit, whether evenly distributed or irregu- 

 larly- raised into hills and ridges, is composed of the rock but a short 

 distance on the north, or perhaps of the one on which it rests, with a 

 constantly decreasing proportion of rocks of northern origin. The 

 materials of the primary rocks constitute but a comparatively small 

 proportion of the superficial accumulations of western New York. The 

 local origin of the drift is shown by the sections everywhere examined. 

 A section on Irondequoit baj^, is as follows: 1. Medina sandstone, 

 shaly with bands of green. 2. Fragments and rolled masses of the 

 sandstone below, with gravel and sand; this contains a few pebbles 

 of the shaly, calcareous saiidstone next on the north. 3. Bed of fine 

 sand. 4. Stratum of sandstone pebbles, cemented into a conglomer- 

 ate by oxide of iron and carbonate of lime. 5. Stratum of pebbles 

 and sand. 6. A course deposit of pebbles of the Medina sandstone 

 below, with gravel and sand. 7. The soil of sandy loam. An- 

 other section 70 miles farther west on the bank of lake Ontario, 

 at the town of Wilson, in Niagara count}', is as follows: 1. Red 

 clay and gravel of the Medina sandstone. 2. Blue clay and gravel. 

 Tlie pebbles are principall}' of the rocks of the Hudson River Group. 

 3. (jravel, clay and sand, of the neighboring rocks, folding over 

 and passing beneath No. 2. 4. The soil of claye}' loam with clay 

 below. The sections of the drift almost universally correspond with 

 these, and their explanation, viz: a bed of broken fragments, with 

 worn pebbles resting upon the rock from which they are derived. The 

 granite and other materials of a far northern origin rarely constituting 

 a part. And where they do form a part, the deposit may have under- 

 gone some subsequent change. 



