80 [Assembly 



ported from north to south. From a bushel of pebbles taken 

 from any gravelbank south of the Erie Canal, the geologist can 

 pick out specimens of almost every stratum which is exposed 

 north of the bed whence they were taken. South of the line of 

 outcrop of the Helderberg limestones, the gravel banks are full 

 of fragments of their different layers ; and among them lie worn 

 pieces of the red Medina sandstone, others of the Hudson-river 

 group, and others of still more northern strata ; while some are 

 granite pebbles, which must in many instances have come from 

 Canada. They have evidently been transported from north to 

 south in vast quantities : they are smooth-worn, and are smaller 

 the farther they are found from their original strata ; they are 

 generally found in irregular layers with sand and clay, as if left 

 so by the action of rapid currents of water* One of the most 

 puzzling facts connected with them is, that they have been in 

 many cases transported from lower to higher levels, even up steep 

 declivities and over high hills. 



There are spread with them also (but generally lying on the 

 surface of the ground) many large and heavy masses of loose 

 rock, called boulders. Some of these are limestones or sand- 

 stones, the origin of which can easily be traced to thin native 

 strata within the State ; others are granitic masses, which must 

 have come from beyond Lake Ontario, in the same manner that 

 the peculiar granitic rocks of the Adirondack mountains are 

 found to have been carried south beyond the Mohawk valley. 

 And the surfaces of the rocky strata in all the country over 

 which these " drift beds" have passed, are in many places found 

 to be worn smooth, and scratched or furrowed in a general north 

 and south, or northwest and southeast direction, as if such heavy 

 materials had been dragged or driven over them. 



Some geologists refer these facts to the operation of glaciers 

 moving from the north over the country, during some supposed 

 epoch of arctic cold ; others think the scratches were made by 

 stones pushed over the bottom by grounding icebergs floating 

 from the north, while the country was submerged ; others believe 

 the gravel and boulders were transported, and the rocks smoothed 

 and worn, by violent currents which were thrown over the land 

 from the north by some convulsion, such as the uplifting of a 

 great tract of northern sea-bottom, which might have poured its 

 waters towards the south in great depth and with enormous 

 force. If must be admitted that none of these theories fully 



