BARRIS OUR LOCAL GEOLOGY. 1 9 



Alveolites goldfussi Billings. 



Spirifer fi^nbriatus Conrad. 



Atrypa reticularis Linnaeus. 



Platyostoma lineata Conrad. 



Phacops rana Green. 



3. — Undetermined fossils: 



Heliophylluiti, Alveolites, Cladopora, with Bellerophon, 

 Euomphalus , and Gomphoceras. 



One Other locality is worthy of a passing notice. Professor Worthen 

 claimed that the whole floor of Rock River, from Camden almost to 

 the Mississippi, is composed of this rock.* He writes: "The massive 

 solidity, conchoidal fracture and white dove-color of the stone indi- 

 cate it belongs to the lower portion of the formation. ' ' Few fossils were 

 found in it when he wrote. Subsequently, when the river was drained, 

 many of the rarer forms were found. 



A few rods from the bridge, in the rise towards the bluff, are the 

 remains of an old quarry in which the upper thinner layers are more 

 than usually thickened and carrying some of the usual fossils in excel- 

 lent condition. 



It is only in the Phragmoceras beds, and confined to their lower 

 portion, that Ganoidal remains have been found. Fragments of 

 plates occur measuring nearly an inch in thickness and several inches 

 in length and breadth. As in other localities, their entire surface is 

 covered with small stellate tubercles. Apparently similar fragments 

 appear among fossils of the Hamilton formation of Ontario, Canada, 

 in their best known localities. These fragments have been formally 

 acknowledged by Whiteaves, in the Geological and Natural History 

 Survey of Canada, as parts of the cranial plates of the Macropetalich- 

 thys Sullivanti Newberry, f at first described from the Corniferous of 

 Ohio. 



SPIRIFER PENNATUS BEDS. 



Between these beds and those just described a marked contrast ex- 

 ists extending to rock and contents. There are soft clays, irregularly 

 bedded, light-colored limestones, often separated by bands of calcar- 

 eous shale, and, in addition, holding a prominent place and maintaining 

 a definite position in these beds, is a persistent encrinal limestone. 



* Geology of Illinois, Vol. V,, page 227. 



•j- Contributions to Canadian Palaeontology. Vol. I , Part II., Sec. 2, page 119. 

 Geological Survey of Ohio. Palaeontology. Vol. I., page 290. 



