NORTHERN AND SOUTHERN KINDERHOOK FAUNAS 625 



attains a maximum thickness of 60 feet, but at Kinderhook the lime- 

 stone layer above the yellow sandstone is but 6 feet in thickness, 

 while at Burlington it has a maximum thickness of 18 feet. At 

 Kinderhook this limestone is but sparsely fossiliferous, although one 

 of the species recognized, Prodiictella pyxidata, is one of the common- 

 est members of the Louisiana Limestone fauna. At Burlington, 

 Iowa, the fauna of the limestone (beds Nos. 3 and 4) above the 

 yellow sandstone of bed No. 2 contains a modified facies of the 

 Chonopectus fauna. Chono pectus fischeri is a common species, and 

 associated with it is Para phorhynchus striatocostatum, which some- 

 times occurs abundantly. This species was originally described from 

 Kinderhook, and, judging from the lithologic characters of specimens 

 from Pike County, Illinois, in the collection of Walker Museum, 

 it occurs in the fine-grained limestone above the yellow sandstone. 

 The same species, in its typical form, has been collected by Professor 

 Rowley in the Louisiana Limestone. 1 Another species binding the 

 fauna of the fine-grained limestone at Burlintgon to that of the 

 Louisiana Limestone is Syringothyris halli Win., which is appar- 

 ently but a small form of S. hannibalensis so characteristic of the 

 Louisiana Limestone. Both of these species are distinct from, but 

 closely allied to, the species of the same genus occurring in the yellow 

 sandstone beds at both Burlington and Kinderhook, and known as 

 S. extenuatiis Hall. 



The interrelationships of the various expressions of the Louisiana- 

 Kinderhook-Burlington faunas under discussion are such as to make 

 their correlation a matter of some certainty. It may be assumed 

 that we have to deal here with one general contemporaneous forma- 

 tion, exhibiting at Louisiana and elsewhere on the Mississippi River 

 a limestone facies throughout, while east and north, at Kinderhook 

 and Burlington, the sediments were largely arenaceous, the conditions 

 for the deposition of calcareous sediments not being introduced until 

 near the close of the time epoch represented. 



Another factor which adds to the strength of the correlation of 



1 The writer has not seen a specimen from the Louisiana Limestone, but Pro- 

 fessor Rowley states that he has collected a very perfect specimen, which is no longer 

 in his collection. Hall and Clarke also illustrate a specimen of this species {Paleon- 

 tology of New York, Vol. VIII, Part II, Plate 60, Figs. 33, 34.) from Pike County, 

 Missouri, which doubtless came from the Louisiana Limestone. 



