320 The Ameticaii Geologist. November, i89>> 
to further assume that water currents were strong enough to 
disturb them at least by moving the clay from around them, 
and to bury them again. The limestone stratum from which 
they came had consolidated before they were formed. The 
sedimentation was interrupted in the same manner two or 
more times during the deposition of the upper third of the 
bed. 
Following the Stictopora bed comes the twenty foot thick 
Fucoid bed, which is the fifth in the series. The bed is a clay 
with calcareous laminae and fucoids interspersed and a few 
firm limestone strata intervening. At or near the top there 
is again oolitic limonite to be found and close below it a few 
cake shaped pebbles two to six inches wide. The top stratum 
is an impure but brittle limestone. Its upper surface when ex- 
posed shows a blackened planed field, with numerous abrupt 
pits and borings characteristic, one might say, of a sea bottom. 
But it is not encrusted by Bryozoa or other fossils. The strat- 
um itself bears no well preserved fossils and seemingly none 
of any kind except fucoids, but these nearly compose all the 
upper strata, and are abundant throughout this bed. Suc- 
ceeding strata are very fossiliferous and minute shells and 
zoaria are often beautifully preserved in large numbers. They 
belong to the Orthisina bed. About nine feet above the 
Fucoid bed the strata contains pebbles similar to those in the 
Stictopora bed, although smaller and more dispersed. They 
lie in the lower half of the Orthisina bed, but at the top of a 
division which I here formerly designated as the Zygospira 
bed. 
It is evident to one examining the Galena series' strata that 
the six beds exposed at Saint Pavil and Minneapolis are separ- 
ated by intervals of non-deposition of sediments. The beds 
are characterized by faunal dififerences and the interruptions 
in the life sequence now appear to coincide with interruptions 
in deposition of sediment. Of course the deposition of sedi- 
ment may have ceased innumerable times during the building 
of the several beds and not infrequently etched shells and 
zoaria bear evidence that they lay long unburied on the sea's 
bottom, but intervals sufficiently long to permit marine erosion 
and corrosion to form blackened unconformable surfaces and 
black manganese stained pebbles, mark the upper parts of the 
