BARRIS — OUR LOCAL GEOLOGY. 1 5 



lections here made — that of the College, the Academy, or my own — 

 were any of the fossils labelled ' ' Corniferous " or " Upper Helderberg. ' ' 



In the present paper, attention is directed not as heretofore to the 

 study of a single fossiliferous rock, but extended to the whole series of 

 which it here forms a part. This series admits of three natural 

 divisions. 



These were first recognized and published by Professor Calvin. To 

 the upper member, as develo])ed at Buffalo and vicinity,* he gave the 

 name of Spirifer Parryanus beds, in view of the presence of that spir- 

 ifer; to the next lower the name Spirifer Pennatus beds, that being its 

 characteristic fossil. To the lowest the writer suggested tlie name of 

 Phragmoceras beds — the Phragvwccras tvalshi being its most marked 

 fossil in this vicinity. The Professor favored its application simply as 

 a convenient local name. The name of each bed thus suggests its 

 distinguishing fossil. 



' It is proposed to invite attention to each of these beds in the order 

 of its exposure, to mark out something of its extent, its character and 

 contents, as exhibited in the various localities on the river, to show 

 the relations these beds sustain each to the other, and the true signifi- 

 cance of such relationshi]). 



THE PHRAGMOCERAS BEDS. 



These comprise the lowest fossil-bearing rocks found in this vicinity. 

 They extend from a point in the eastern portion of the city, and are 

 seen on both sides of the river as far west as the Cook quarries. They 

 also appear on Rock River, near Camden, Illinois. 



The earliest indication of their exi.stence is furnished by the dis- 

 covery of the trilobite known as the Proetus Proiiti of Shumard.f In 

 his description of it, he writes: "I am indebted to the kindness of 

 ray friend, Dr. H. A. Prout of this city, who found it some years ago 

 a short distance above tlie town of Davenport, Iowa, near the water level 

 of the Mississippi, in 'compact grey limestone' supposed to be of the 

 age of the Hamilton Group of the New York series." This compact 

 grey limestone of which he writes is one of the persistent elements of 

 the Phragmoceras beds. While every vestige of the rock /// place has 

 disappeared, the original specimen on which Shumard based his 

 description was lost in the great fire at St. Louis, which swept away 

 his whole collection. Fortunately a second and third specimen 



* Natural History Bulletin of the Laboratories of the State University of Iowa, Vol. L , 

 page 26. 



tTransactions of the Academy of Science of St. Louis, Vol, IL, No. i, page iii. 



