Geology of Massachusetts. 5 
in modifying the loose coverings of the rocks. ‘This aqueous agency 
has often covered one rock with the spoils of another; and some- 
times mixed together the worn off fragments of half a dozen, and 
accumulated them in immense quantities in particular districts. 
These circumstances have rendered the subject under considera- 
tion an extremely difficult one; and very few general principles 
have yet been settled concerning it. Indeed, so far as I know, little 
attention has been given to it in this, or other countries. Still, there 
_is such a thing as peculiarity of soil, occasioned by the peculiarity of 
the rock from which it principally proceeded. Ishall notice any pe- 
culiarities of this kind, that have struck me, in the soils of Massachu- 
setts; but I shall not enjoy the advantage of comparison, not having 
found more than one or two observations of a similar kind, made on 
the eastern continent. I shall begin with the stratum that lies above 
every other :—viz. 
Alluvium. 
In this part of my Report, I shall not enter into a systematic and 
minute description of the various formations represented on the ac- 
companying map. Such description belongs more appropriately to 
the scientific part. I shall here describe the different strata only so 
far as is necessary to the particular purpose I have in vie-v. 
Alluvium is that fine loamy deposit, which is yearly forming from 
the sediment of running waters, chiefly by the inundations of rivers. 
It is made up, of course, of the finest and richest portions of every 
soil over which the waters have passed. Hence alluvial meadows 
have always been celebrated for their fertility. No extensive allu- 
vial tracts occur in Massachusetts; although limited patches of this 
stratum exist not unfrequently along the banks of every stream, and 
with the adjoining elevated ground covered by wood and pasture, con- 
stitute not a few of the most productive farms in the State. Even 
where Deerfield river winds its way among the lofty and precipitous 
spurs of Hoosac mountain, which crowd so close upon the path as 
almost to throw it into the shade at noon-day, the traveller is sometimes 
agreeably surprised to see a luxuriant meadow open before him, re- 
warding the labors of some thrifty farmer. No alluvial tracts, how- 
ever, have been thought of sufficient extent to deserve » place on 
the map, except one or two salt marshes a little northeast of Boston, 
and several meadows along the Connecticut, Deerfield, and Housa- 
tonic. These of Longmeadow, Springfield, Northampton, Hadley, 
Hatfield, Deerfield, and Northfield, have long been celebrated for 
