ARRANGEMENT. 



Fio. 41. 



FIG. 42. 



2 ft. 



Fig. 41 exhibits a section of a lateral terrace upon a small stream emptying at Williamsville, into a 

 branch (Rock River) of West River. The thickness of the terrace is about twelve feet, and its height 

 above the river about twenty-five feet. It is composed of sand, 

 B, and coarse gravel, A. The sand is quite fine, and the gravel 

 very coarse, many of the pebbles being a foot in diameter. The 

 gravel bed is of uniform thickness two feet and shows no 

 marks of stratification. Besides the sorting process, tin's section 

 shows that a portion of sand has been removed previously to the 

 deposition of the gravel, the amount of which we can only con- 

 jecture. 



Similar sections to this are found in many parts of the State. 

 Our note books contain sketches of some in the upper part of 

 the valley of the Passumpsic River. There the beds of alluvial Section in a Terrace at Williamsville. 



deposits are finely exhibited in the excavations made for the track of the Connecticut and Passumpsic 

 River Railroad. Sometimes the bed A in the figure is reduced to a few inches of thickness, and then 

 does not seem to have been deposited by water, but accumulated gradually by the mingling together of 

 loose portions of sand with vegetable matter, thus forming a soil. 



We give from Rev. S. R. Hall's Report to Prof. Adams in 1846, two sections of interesting alternations and 



changes of material in different strata. They are sections of terraces. 

 " Near the village in Bethel on White River, there was a hill, per- 

 haps twenty feet high, which when I was there was being removed 

 for constructing the railroad. The different kinds of materials are 

 arranged as in Fig. 42, and with the thickness represented by the 2 ft., 

 3 ft., etc. on the left side of the figure. The third layer from the top 

 of the sand was somewhat curved upwards, the rest were nearly hori- 

 zontal. About four feet of the lowest layer of sand were exposed, 

 and the sand extended deeper still into the earth. The summit 

 of the hill where nearly level, contained, several square rods of 

 surface. 



"A still more irregular arrangement of clay, sand and gravel is 

 seen, where a cut is made for the railroad at Windsor, on the south 

 side of the ' Hour-Glass'. The great proportion of this hill is loose 

 gravel and river deposits, as seen where the stream has washed away 

 the south side of the hill. On the south side of the hill, half a mile distant, the material is principally 

 cky, or clayey sand. Fig. 43 represents a perpendicular section of that part of the hill left on the east 

 side of the excavation. From the top is a steep descent 

 to the river, some 150 feet below. The very crooked 

 line (zig zag) near the top represents a narrow stratum 

 of gravel in the clay, nearly horizontal in its general 

 direction but exceedingly contorted when traced spe- 

 cifically. 



" The height of the section is twenty feet. The clay 

 appears to have been deposited upon the sand in still 

 water, after the sand had been accumulated and par- 

 tially worn away. The clay is horizontally stratified, 

 as well as the sand, 



"At St. Johnsbury, half a mile south of the plain, is 

 a bank where a narrow stratum of clay rests on sand. 

 Above the clay is a deposit of gravel, several feet thick. 



"From Hon. William C. Bradley, of Westminister, Section of a Terrace in Windsor. 



4./J. 



Clay. 



Gravel. 



Sand. 



Clay. 



Sand. 



Section of a Terrace at Bethel. 



FIG. 43. 

 Summit of Terrace. 



Gravel. 



( In:/. 



Smut. 



