Cotiglomerates in the Galena Series. — Sardeson. 321 
beds as described. The seeming exception in the lower part 
of the first bed or Buff limestone may rather be in accord with 
the rule and the strata between the corrosion zone and the 
Saint Peter sandstone should accordingly be designated a 
distinct bed. Heretofore this part has been called the "trans- 
ition" although the paucity of fossils and its rare exposures 
have left us in doubt whether or not it is a distinct faunal 
zone. Recent investigation of it has resulted in the finding of 
several species all but one of which occur in the overlying bed ; 
the one species however is quite strange and has not yet been 
identified. It is an Ophileta. In the Stictopora bed the last 
twelve feet of the 30 or 35 feet bear first a conglomerate, then 
an oolyte zone and possibly other lesser conglomerate zones 
besides the chief one at its top. This part of the Stictopora 
bed seems the most irregular in thickness of any part of the 
series, although one can not be certain of that because its 
position in the middle of the shales causes it to be seldom 
well exposed. An attempt to dehmit it faunally, following 
the suggestion of E. O. Ulrich has not resulted successfully 
except in so far as it has been proved that Rhynchonella ains- 
liei N. H. W. recurs in this part of the Stictopora bed, and 
that it is the zone of the rare Leptaena haUi Sar. It is highly 
fossiliferous. In general it bears the same relation to this 
bed as the few inches of conglomeratic shales at the top of 
the Stictoporella bed do to that one (see platelX). The con- 
glomerate zone in the Orthisina bed which is nearer the bot- 
tom than the top, lies however at the top of a faunal zone, 
which might be designated by a separate name but which 
could not however be distinguished in other places, because 
of imperfect preservation. 
The rule is then without exception here that the sedimen- 
tary small non-conformities coincide with faunal changes and 
these both may be assumed to have a common cause, namely, 
intervals of no sedimentation in their time. This relationship 
may be useful as an aid to correlation of the related forma- 
tions. 
At Saint Paul and Minneapolis the strata are well pre- 
served and w^hen they are exposed by quarrying the described 
phenomena can be well observed. None of the rocks, as a 
rule, are altered to a vesicular texture as in the Galena series 
