34 The American Geologist. January, 1897 
presented is intended to enable geologists who are eontined to 
restricted areas, to present their observations in such form 
that they may be of greater use in the study of the history 
belonging to the Galena and Maquoketa deposits and their 
faunas. 
The beds one and two have had nearly' the same primitive 
sedimentary characters throughout, aiul their faunas are like- 
wise uniform in areal distribution. Beds three to five are 
limestone in the south and east, but mainly clay of shallow 
water deposition to the northwest, and their faunas are found 
to be locally different, in part because of different degrees of 
preservation, in part because some species like OrthiH dajiecta 
Con., never existed except in the limestone areas. From the 
base of the Galena towards its top there is a gradual con- 
vergence back to a widelj'- uniform condition. The bed No. 
10, that forms the transition formation to the Maquoketa 
series is less lacking in uniformity than its outward appear- 
ance would indicate. The beds of the Maquoketa formation 
(il and 12) have local phases in predominance and merely the 
dark, carbonaceous color is the widest noted character. The 
Maquoketa formation is intei'calated into the series, so to say, 
and only towards the top, and more particularly in the suc- 
ceeding Leptaena bed is there a return toward the character- 
istics of the bed (10) beneath it. In the last of the series of 
beds there is evidence that a shore was not far north of the 
Iowa and Minnesota state boundary. And the top of the bed 
in Iowa shows evidence of iron deposits, as it does notably in 
eastern Wisconsin. In Wisconsin, Illinois and Iowa the Ni- 
agara limestones, in southeastern Minnesota the Devonian 
rests upon the Maquoketa series, there being thus a varying 
interval of no deposit following it. 
One cannot fail to note the large numbers of Trenton and 
Hudson species of fossils that are found in the Galena and 
Maquoketa respectively, but there are instructive differences, 
such as the continuance of the Trenton form of Orthis [Platy- 
strophia) biforata from bed No. 5 through both Galena and 
Maquoketa series, the Hudson "varieties" 0. lynx, 0. acutil- 
irata etc., not being found. Again the trilobite genus Illanius 
is strangely not represented in my collections from the Ma- 
quoketa series but is found in all beds of the Galena series. 
