212 GEOLOGY OF THE THIRD DISTRICT. 



CHAPTER VIII. 



QUATERNARY DEPOSITS. 



These, as mentioned in the table of contents, consist of two kinds or orders. The first 

 embraces those which have been transported from a greater or less distance, as clay generally, 

 sand, gravel, boulders, etc., and are commonly known by the name of alluvial deposits, or 

 products of alluvion or alluvium. The second kind or order are the result of deposits in 

 place from solution, as lake marl, calcareous tufa, ferruginous tufa ; or of products of vegeta- 

 tion, as peat or muck. With respect to soil, it belongs to either, and should, from its impor- 

 tance, be made an order by itself. In this enumeration, the products of the decomposition of 

 rocks in place, or, in other words, in the position they were originated, are not noticed, as not 

 being of sufficient importance in the district, and as being included in soils. 



Allittial Deposits. 



The Mohawk river and its tributaries show a determinate order of alluvial deposits. So 

 also there appears to be a like order through the great level, and no doubt the same prevails 

 in the valleys south, but was not so generally noticed, but few excavations having been ob- 

 served. The deposits of the three sections are not, however, in accordance with each other. 

 Along the Mohawk river, and in many of its tributaries, the lowest deposit generally which 

 was observed is a tenacious blue clay, similar to that of Albany, which becomes of a brownish 

 color when long exposed ; the top of the mass usually of that color, and less adhesive. In 

 some places it shows alternations of sand more or less regularly disposed, the clay generally 

 covered with sand more or less thick, upon which not unfrequently there is a third deposit, 

 consisting of rolled stones, intermixed with loam ; the stones consisting in greater part of 

 primary rock, and red and grey sandstone, the two latter in greater number than the former. 

 The deposits are so numerous, that those only of magnitude can be noticed. 



They commence on the south side of the Mohawk, and continue by Port Jackson to near 

 Auriesville. On the north side, the same deposit appears between Amsterdam and Tripes 

 hill, and to the west of the hill. Its point of greatest magnitude is on the same side between 

 Fonda and the east end of the uplift of the Noses, extending north by the side of the cliff, 

 and rising from forty to sixty and eighty feet above the river. On the south side, the blue 

 clay appears in the road, at the east end of the uplift, near the cliff. Further east, there is a 

 level surface, rising about twenty feet above the river, showing numerous rolled stones resem- 

 bling a river bottom. And again still further down the river, there is another river bottom 

 over which the road passes, and is raised about sixty feet above the river ; it is thickly strewed 

 with river stones, and covered with a grovrth of pines. 



