American Association. , 285 



taetamorphofeed more or less. He proposed to occupy a few 

 moments in following the direction of the ancient cm'renls, and to 

 show their parallelism with the mountain chains in the Laurentian 

 Mountains, north-east of them, which are nearly parallel to the 

 Appalachian chain. The Geological Survey would show whether 

 these sediments were thicker to the eastward than to the west- 

 ward ; but he thought the direction of the currents, which de- 

 posited the materials forming the Appalachian chain, was froiii 

 the north-east. They had certainly good^ evidence from the fact 

 that the strata are of the same age, and are much thicker from 

 the north-easterly direction than from the south-west. They 

 gradually thin in that direction, and, as he beheved they were 

 deposited by water, the further from the source they would be 

 the thinner. They had reason to believe that in the south-west 

 these strata were much thinner than in the north. Taking the 

 Hudson River group which consists of sediments stretching to 

 the south west, with a thickness of 1000 feet to the north east of 

 us, it thins down to 600 feet in Pennsylvania, and finally in the 

 Mississippi valley the thickness is not more than 100 feet. Pass- 

 ing from the Hudson river group and over a lapse of time, to the 

 Oriskany Sandstone we find the deposits from the north east. 

 At Gaspe the thickness is 7000 feet, in New York it is reduced to 

 a few hundred feet and the stata thin out in a westerly direction. 

 The conclusion he had arrived at was that along these lines of 

 deposit where the greatest accumulation of sediment has been 

 made, and where we have the greatest elevation of mountain 

 chains, this merely coincides with the direction of the ancient 

 currents, and that the Appalachian mountain range has not been 

 more uplifted than the other portions of the country, or than the 

 plain between these and the Atlantic. In New York and Penn- 

 sylvania they got to the Potsdam Sandstone, and, therefore, therfe 

 was no uplifting of any previously existing rocks before the Appa- 

 lachian chain. The folding and plication had commenced at an 

 early period — at a period before the upper Silurian Rocks were 

 formed, and we find these strata plicated and uplifted and had 

 metamorphosed in a considerable degree. We get no lower 

 than the Potsdam Sandstone in any part of the Appalachian 

 chain, and we can demonstrate that no lower mass has had any- 

 thing to do in giving us the elevation of this mountain chain. 

 The Prof, then referred to his examination into other formations 

 in confirmation of his hypothesis that elevating forces had not 



