224 GEOLOGY OF THE THmD DISTRICT. 



In Russia, according to the recent report of Messrs. Murchison and Vemeuil, the operation 

 of raising blocks of rock from a lower to a higher level for example, is well exhibited at about 

 eighty miles above Archangel, where a range of angular blocks of white limestone is piled 

 up about twenty or thirty feet above the river. This has been effected by the freezing of the 

 water around the blocks at the water line, the spring freshet raising and drifting the whole t» 

 the new shore ; and by thawing, the blocks are deposited at a higher level. The same ope- 

 ration, with the drift from north to south, is more in accordance with the general fact in New- 

 York, than that of marine submergence and icebergs. The absence of all marine produc- 

 tions whatever, excepting those which form a part of the ancient materials of the alluvial, 

 are in opposition to any but a very transient submergence, hardly suflScing to explain the 

 number of boulders which have been let down or cast upon the surface, and leaving wholly 

 unexplained the prodigious amount of northern drift in the form of paving stones, pebbles 

 large and small, sand and earth, which exists all over the counties south of the Mohawk 

 valley or Helderberg range, these drifted materials extending even into Pennsylvania. 



An opinion prevails in the United States, that the whole of the boulders have been carried 

 firom north to south, and hence a flow or flood of water from the north has been adopted. 

 This is fully negatived by the northern primary nucleus of New-York ; and when that of the 

 eastern range in New-Hampshire is examined in all its directions, the facts observed in New- 

 York will be found to be common to both. In the third district the boulders of primary rock 

 are found to the west and the northwest, as well as on the south side of the primary nucleus 

 from whence they originated ; and from the observations of Dr. Emmons, they occur also on 

 the north and the east side of the same nucleus ; confirming the great fact recorded in Europe, 

 that they are not the result of a flow in one direction, but as it were radiate from a common 

 centre or centres ; or in other words, have been distributed oa all sides from central upraised 

 or upraising primary masses. This is a necessary conclusion, since the primary masses 

 which give origin to the greater number of the northern boulders now elevated five and six 

 thousand feet above the ocean, were once the lowest as to altitude, and were raised in modem 

 eras ; but so long as observations were confined to the south side of these upraised nuclei, 

 as matter of fact no other origin could be given to their boulders, but the one so generally 

 entertained and published. 



Lake Marl. 



This substance is a carbonate of hme, which has separated from its solvent, in water ; the 

 latter preventing its particles from cohering together, and allowing them to subside in the state 

 of a calcareous mud. It is in many places constantly depositing from waters holding Ume- 

 stone in solution. 



In the third district, there are two sources from whence its material was derived : The first 

 and greatest is from the calcareous rocks, and is found in great abundance north of the Hel- 

 derberg range, and in some of the valleys of the range ; the other kind appears to have been 

 derived from calcareous alluvion, and is found chiefly to the south of the range. 



