124 Trans. Acad. Sci. of St. Louis. 



specimens described by Winchell as jS. Halli are smaller 

 than the Louisiana examples. 



If it be true that bed No. 4 is the northern extension of the 

 Louisiana limestone, then the Chonopectus sandstone and the 

 underlying shales would be included in the Devonian accord- 

 ing to Keyes'* interpretation of the Kinderhook. The basis 

 for his determination of the Devonian age of the Louisiana 

 limestone, however, seems not to be well founded. The fact 

 that in a single vertical section like that at Louisiana, includ- 

 ing several diverse lithologic formations, a line can be drawn, 

 above and below which there are no species of fossils in com- 

 mon, does not necessarily indicate a profound life break. 

 From a broad point of view this is seen possibly to 

 indicate only a change in local conditions such as to cause a 

 shifting in the geographic distribution of life. In almost any 

 geologic section of any considerable thickness, in which there 

 are diverse lithologic formations, no matter to what geologic 

 period it may belong, there may be found just such profound 

 life breaks, but judgment must be used in the interpretation 

 of these faunal changes. 



It is not the writer's intention to positively deny the con- 

 temporaneity of a portion, perhaps a large portion, of the 

 Kinderhook beds with some of the beds referred to the 

 uppermost Devonian in other portions of the continent, but 

 if any part of them are Devonian, the evidence of their 

 age will have to be of a more substantial nature than that 

 offered by Keyes. There are certainly Devonian elements in 

 the fauna of the Louisiana limestone, but there also are con- 

 spicuous elements of Devonian life in some formations of the 

 age of the St. Louis limestone, f and yet no one would insist 

 for a moment on their Devonian age. The Chonopectus 

 sandstone also possesses a strong Devonian element in some 

 particulars, — it is far more strongly Devonian than the fauna 

 of the Louisiana limestone, — but in both faunas there is an- 

 other element of perhaps greater significance binding them 

 to the Carboniferous. 



* Trans. Acad. Sci. St. Louis. 7 : 357. (1897.) 

 t Am. Jour. Sci. III. 49 : 94. 



