FA UNA OF DF VON I A A ' FORMA Tl ON A T MIL WA UKEE 275 



impressions. Almost the only ones which are well preserved are 

 specimens of Liiigula, Orbiculoidea and Conularia ; the plates, 

 scales and teeth of fishes ; and some plant remains in carbonized 

 form. At the top of this section is a very hard layer about six 

 feet in thickness, containing cavities lined with crystals of calcite 

 and pyrite. This layer is very rich in fossils, very few forms 

 being absent from it which are found in any part of the quarry ; 

 and itis especially distinguished by the multitudeof its cephalopod 

 and fish remains. The layers below this one are softer, some of 

 them very soft indeed, and are on the whole less rich in fossils ; 

 but the surfaces of some of the lower layers are covered with 

 pyritized shells of brachiopods, mainly Chonetes scitulus Hall, of 

 the gibbous form, and Delthyris consobrina D'Orb. 



The upper subdivision comprises the upper four feet of the 

 quarry. Its surface has been smoothed by glacial action. Most 

 of its fossils are found as casts in the section below, but here the 

 shells are often preserved. Much of the rock of this division is 

 of a lumpy, nodular character, and suffers rapid disintegration 

 under atmospheric influences, the fossils weathering out. 



These two sections, at the lake and at the river, are not pre- 

 cisely alike but are easily correlated with each other. The entire 

 series of Milwaukee Devonian rocks may therefore be conven- 

 iently subdivided as follows, the section at the water tunnel 

 being designated A, and the section at the cement quarries B. 



A 4. The Lingula-bearing shales. 



A 3. That portion of the " soapstone " carrying shells of 

 Spirifer euryteines Owen, .S. asper Hall, and Atrypa reticularis L., 

 and the flat variety of Ownetes scitulus Hall ; being the upper 

 "soapstone" of the City Engineer's section. 



A 2. This includes the thin hard layers so rich in specimens 

 of the gibbous variety of Chonetes scitulus Hall, and Tentaculites 

 bcllulus Hall. It also includes portions of "soapstone," probably 

 the lower " soapstone " of the City Engineer's section, containing 

 the same variety of C. scitulus Hall, and Couularia. Its relations 

 seem to be with subdivision B I of the quarry rock. 



