$ 
(II) 
carried away, I rather incline to the belief that these rocks were 
never covered in carboniferous times, but formed then an island 
around which such rocks were deposited. This island embraced 
the greater part of Newport Neck, the entire harbor, and a por¬ 
tion of Conanicut, and accordingly measured some four miles in 
diameter ; so that as we ramble over the small hilly and rocky 
wilderness which characterizes portions of the Neck and of 
Conanicut, we may transport ourselves in imagination back to the 
time when in looking away our eyes would have rested on nothing 
but a shallow sea, or else upon great swamps crowded with the 
peculiar vegetation of the carboniferous time. The remainder of 
Conanicut and of our own island, excepting perhaps a small tract 
at its northern extremity and possibly another at Paradise, were 
not in existence ; with these exceptions the nearest terra firma was 
at Tower Hill and Little Compton. 
The carboniferous series, as before stated, consists of four groups 
of strata :—(i) the metamorphic grit, (2) the clay slates with car¬ 
bonate of iron, (3) the quartzyte conglomerate, and (4) the slates, 
coal beds and fine conglomerates, which together constitute the coal 
measures proper. During the deposition of the two first and low¬ 
est of the series, there was nothing of a very exceptional charac¬ 
ter in the physical conditions of our bay. The fine quartz grains 
of the first deposit probably came from the erosion of some areas of 
granite or protogine. The presence of fossil plants in the layers 
of slate, which occur in this bed, indicates the neighborhood of 
marshes; and the abundance of iron carbonate in the succeeding 
bed shows the presence of carbon in the water and originally in 
the atmosphere. During these depositions, it is quite probable 
that that process of subsidence commenced which marked the 
period of the coal measures. This subsidence would affect the 
whole region, but, either owing to its taking the form of great 
folds, or owing to the greater elevation of the central island, would 
still leave that island above water. But during the time of the 
third group, the coarse conglomerate, we have evidence of an ex¬ 
ceptional state of things. The great size of some of the boulders 
in the conglomerate at “Purgatory” and “Paradise” has been 
noticed by many. Some of these measure from four to nine feet 
in diameter. 
