Physics and Astronomy. 309 



It is probable that the present Austin New Braunfels non- 

 conformity continued to Red river, and that future stratigraphic 

 study will demonstrate this. It is nearly obliterated by a 

 more excessive denudation there, but a portion of the old 

 plateau exists in the Grand Prairie, between the Upper and the 

 Lower Cross Timbers. This plateau is clearly the remnant of 

 an elevation previous to the deposition of all the hitherto 

 marine Cretaceous of America, although it was submerged 

 again in parts, as is seen by the deposition of later formations 

 upon it. 



I have shown by methods of stratigraphic paleontology that 

 we have in Texas not only the most complete section of the 

 purely marine formations of the Cretaceous of the United 

 States, but we have a well-defined series of marine strata of 

 much lower horizon than heretofore supposed to exist in this 

 country, which when they are properly studied, will eliminate 

 the supposed hiatus of deposition which has been thought to 

 exist between Jurassic or Wealden, and middle upper portion 

 of the Middle Cretaceous of this country. In fact, we have in 

 Texas, along the region described in this paper, the most of a 

 section of the Cretaceous and other Mesozoic which, from its 

 approximate completeness, must in the future be looked upon as 

 the standard of comparison in the study of the Mesozoics of this 

 country, just as the Paleozoic formations of the Appalachian 

 region are accepted as our standard for earlier time. 



For the present we can only divide the American Cretaceous 

 section into generalized Upper, Middle and Lower divisions. 

 When, by modern methods of stratigraphic paleontology, this 

 Texas region is more thoroughly studied, we shall have a sim- 

 ple comprehensive section of the entire period, which will serve 

 as a standard of comparison, owing to its greater development 

 and transitional geographic position for both the Rocky Moun- 

 tain and Atlantic regions, and as a basis for an intelligible and 

 rational nomenclature Until this is done all attempts at a 

 fixed nomenclature of the American Cretaceous must remain 

 unsatisfactory and provisional. 



SCIENTIFIC INTELLIGENCE. 



I. Physics and Astronomy. 



1. Annalen der Physik und Chemie, No. 8 b , for 18SV, con- 

 tains the following articles; On a new polar effect of magnetism 

 upon the heat produced by the electric current in certain substances y 

 by Albeet von Ettingshausejst. — The author finds that a tem- 

 perature difference obtains in a magnetic field and discusses the 



