92 YEARBOOK, PUBLIC MUSEUM, MILWAUKEE. [Vol. I. 



The "hlue shale" of the horings is apparently fossiliferous through- 

 out its entire thickness. This memlDer can be separated into several 

 distinct horizons of which a soft clay shale carries the most varied 

 fauna as well as the greatest number of individuals. This rock is very 

 fine-grained and homogeneous, having a greasy feel and weathering into 

 a sticky blue clay. It abounds in fossils ; notably fish remains, brachio- 

 pods and pelecypods. Among the brachiopods, the most characteristic 

 are, Productella. Orthids, Chonetes, Ambocoelia, Stropheodonta (rare), 

 Liorhynchus, Lingula (not common), and a species resembling Craniella. 

 Among the pelecypods, Paleoneilo and Lunulicardium ( ?) predominate. 

 Fragmentary Goniatites and a single specimen of Orthoceras represent 

 the Cephalopoda. 



Closely associated with these shales were large blocks of massive 

 greenish dolomite which weathers to a yellowish color. The fauna of 

 this bed consists largely of fish remains and poorly preserved plants, be- 

 sides which a few brachiopods, probably Orbiculoidea, were collected. 

 Calcite, marcasite, and sphalerite occur in cavities in this rock. This 

 fauna is also found in a bed transitional between the dolomite and the 

 blue shale. 



The "black shale" of the borings consists of a considerable thickness 

 of thin-bedded shales without organic remains, excepting traces of 

 plants, in which are numerous bands carrying conspicuous faunules. 

 The black shales frequently contain nodules of pyrite, masses of asphalt- 

 um, and seams of coal, the latter occasionally approaching an inch in 

 thickness. 



Of the fossiliferous bands occurring in this member, the most con- 

 spicuous are the Lingulae horizons of which three have been differenti- 

 ated. These are each characterized by diflferent species of Lingula, as 

 yet undetermined, and are devoid of other fossils. They are closely as- 

 sociated in the section, one of them being in a very dark shale and the 

 other two in greenish rock of somewhat coarser grain. Very little 

 can be made out concerning the actual relations of these rocks because 

 of their mixture on the dump. However, one of the greenish Lingula 

 bands is frequently found in the same block with another fossiliferous 

 horizon characterized by the presence of conodonts. The two bands are 

 regularly separated by ten to twelve inches of the ordinary black shale 

 which comprises most of the rock of this member. This conodont layer 

 is less than an inch in thickness but, is one of the most important ho- 

 rizons in this series. Numerous species of conodonts occur in a ground- 

 mass of phosphatic material, argillaceous sediments and grains and 



