1921] EDWARDS AND RAASCH, UPPER DEVONIAN STRATA. 91 



a brown shale at the base, followed by bluish shale which, in turn, is 

 succeeded by a black shale immediately underlying the drift. The rela- 

 tive thickness of these three shales varies somewhat in each boring, but 

 the total thickness of the group seems to average about fifty-five feet. 

 The section is not complete and the amount of the upper beds removed 

 by erosion cannot be determined. That this erosion has been of consid- 

 erable extent, is shown by the fact that, in the boring at the extreme end 

 of the tunnel, the upper division has been entirely removed and the blue 

 shale greatly reduced although both are present nearer the shore. The 

 black shale is also absent at the shoreward end of this tunnel, showing 

 that only outliers of this member are present along this section of the 

 coast of Wisconsin. Two of these are now known ; the first having been 

 penetrated by the shaft of the North Point Intake Tunnel, and the 

 second ])y the Lin wood Avenue Tunnel. 



The material excavated from these tunnels was piled miscellaneously 

 upon the shore of the lake. The junior author first discovered the pres- 

 ence of fossils in this material and extensive collections were made all of 

 which are now in the possession of the Public Museum of Milwaukee. 

 This material has now been partially destroyed by weathering and the 

 remainder l^uried by the construction of a parkway along the lake front. 

 Further collecting of these fossils is, therefore, impossil)le unless excava- 

 tions are undertaken in this vicinity in the future. It is probable that 

 these rocks have a considerable area of outcrop underneath the va/ers 

 of Lake ^Michigan as fragments of them are found in the drift as far 

 north as Ozaukee county. 



The various types of rock occurring in the material taken from the 

 excavations can be roughly assigned to the divisions recognized by the 

 engineers in the records of the borings. No opportunity of entering 

 the tunnel for the examination of the strata was afiforded the writers and 

 consequently no direct stratigraphic evidence could be obtained. 



The "brown shale" of the borings is apparently represented by shales 

 containing two separate faunules. The more important of these is a 

 faunule occurring in dark and greenish shales and characterized by the 

 abundance of a small species of Lingula. A single species of Orbicu- 

 loidea and fish remains are also found at this horizon. At another 

 horizon, Conularia is encountered in shales closely resembling those 

 carrying the Lingula faunule. These two horizons were reported from 

 the excavations at the North Point Intake Tunnel where they im- 

 mediately overlie the Hamilton beds. 



