218 Connecticut River Valley. 
and regular slopes, but the various distance, and occasional disap- 
pearance of the higher plains, on opposite sides of the river. 
Summary.—Thus rocks have been converted into sand and clay— 
currents have swept along the prepared materials and deposited 
them in layers—successive breaches of the barriers lowered the bed 
of the river to corresponding depths,—the river in its new channels 
rearranged the sand and clay into lower plains, and finally m mea- 
dows. ‘The remains of these progressive and various changes, con- 
stitute the alluvial formations of the Connecticut river valley. 
V. Primitive Rock. 
It must be perfectly understood, that the whole superficial cover- 
ing of earth on hills and mountains, as likewise the alluvial formations, 
rest upon a sub-stratum of solid rock. Diversity in the substance, 
arrangement and coherence of the component parts of rock, have 
led to their division into classes. ‘The primitive class is distinguished 
by being purely mineral, and semi-crystalline. In general it contains 
no fragments of rock, and no remains of vegetable, animal, or ma- 
rine productions. From the sources of Connecticut river, to the 
north line of Massachusetts, all the rocky strata belong to the primi- 
tive class, and generally, the sides and summits of the valley to Long 
Island Sound. 
VI. Seconpary Formation. 
Locality.—In Northfield, near the northern boundary of Massa- 
chusetts, rocky strata appear, diverse in several particulars from rocks 
of the primitive class. ‘They are composed of fragments, pebbles, 
gravel, sand, clay, lime and other ingredients of primitive rock, re- 
united in strata by an invisible cement. ‘They are not purely mineral, 
like the primitive, but contain remains of plants, fishes, and animals. 
The color of the strata is commonly red or brown. From the man- 
ner and materials of their composition, rocks of this class are denomi- 
nated a secondary formation, sometimes a sandstone formation. Be- 
ginning at Northfield, the border of the secondary formation may be 
traced, east of the river, in Montague, Sunderland, Amherst, Granby, 
Ludlow, Springfield, Wilbraham, Mass., and Somers, Ellington, 
Manchester, Glastenbury, and Chatham, where crossing Connecticut 
river, the eastern border proceeds through Middletown, Durham, and 
East Haven, to Long Island Sound. The western margin of the 
sandstone formation passes from Northfield into Bernardston, Green- 
