90 PROCEEDINGS OF THE ACADEMY OF [1895. 



great rivers : Brazos, Colorado, and Rio Grande, flowing across the 

 Tertiary areas of the State, and the results of his examination have 

 been published in the First Annual Report of the present Geologi- 

 cal Survey. 5 Since that time the work of examining these beds has 

 been carried on continuously throughout the eastern portion of the 

 State almost altogether by myself, and the detailed results of these 

 examinations, chiefly from a stratigraphic standpoint, have been 

 published from time to time in the various Annual Reports of the 

 Survey. 6 



During the course of these examinations Prof. Penrose's river sec- 

 tion along the Brazos was re-examined, the section seen along the 

 Trinity River, and another extended section between the Trinity and 

 Sabine made, and extensive areas throughout other portions of East 

 Texas, were examined in detail. 7 



While a great portion of the stratigraphy had thus been worked 

 out it has only been within the last year that any of the immense 

 collections of fossils obtained during the course of the work have 

 been critically examined and described. 8 



While the prediction of Dall as to the richness of the fauna of the 

 Texas section has been fully verified, various other conditions have 

 come to light which, while they largely verify the Alabama section, 

 at the same time add strength to the all- important fact that 

 the geological conformation of neighboring States cannot always be 

 relied upon as a guide to the geology of any portion of the southern 

 or Gulf Tertiary. 



A comparison of the two sections — Alabama and Texas — shows 

 several material differences between which, prior to the work of 

 the present Geological Survey, were never suspected to exist. The 

 three sections of the Eocene, viz. : Alabama, Mr. Harris' section, 

 and the Texas section as made by the State Survey, are here 

 given for comparison. 



3 Preliminary Report on the Geol. of the Gulf Tertiary of Texas, by R. A. F. 

 Penrose, Jr., First Annual Eeport Geol. Survey of Texas, pp. 6-64. 



6 Second, Third and Fourth Annual Reports Geol. Survey of Texas. 



7 Third Annual Report Geol. Survey of Texas, pp. 43-124 ; Fourth Annual Ee- 

 port (ieol. Survey of Texas, pp. 43-53 and 67-76. 



8 For this work see Monograph of Texas Tertiary Fossils, by Gilbert D. Harris. 



