172 E. A. SMITH PIONEERS IN GULF COASTAL PLAIN GEOLOGY 



2. The outline geological study and mapping of these two states. 



He was the first to give a clear and defijiite account of the origin and dis- 

 tribution of the surface formation which he called Orange Sand, but which 

 later by agreement has received the name Lafayette. While some ques- 

 tion has arisen during the last few 3'ears as to the appropriateness of the 

 name Lafayette, I think time will confirm Hilgard's conclusions as to the 

 existence of a surface formation over the area of the Gulf Coastal Plain, 

 by w^hatever name it be called, and as to the general mode of its accumu- 

 lation. 



So, also, he was the first to give a definite account of the great series of 

 river and estuarine deposits, the Grand Gulf, representing, as he claimed, 

 all geological time between the Yicksburg and the Lafayette, although no 

 recognizable fossils had been observed by him. 



The finding in the last few 3''ears of beds containing leaf impressions 

 in various parts of this territory and their identification as Lower Oligo- 

 cene, Upper Oligocene, Miocene, and Pliocene, respectively, appear to 

 demonstrate the correctness of Hilgard's original conclusion, and the 

 name Grand Gulf will probably stand or should stand not perhaps as a 

 formation name, but as the collective name of a very definite and appar- 

 ently unique t}^e of Coastal Plain sediments, or shall I say Mississippi 

 River sediments ? 



3. The recognition of the Cretaceous Eidge or backbone of Louisiana, 

 from Lake Bistineau to the chain of Salt Islands, and the determination 

 (inferential) of the Cretaceous age of the rock-salt and sulphur deposits 

 of Calcasieu parish. 



4. Study of the exceptional features of the Lower Mississippi delta 

 and of the mud lumps and their origin and the definite correlation of the 

 Port Hudson formation. 



This work on the Mississippi delta mainly secured for him member- 

 ship in the N"ational Academy of Sciences. 



The geology and other natural features of Louisiana have been treated 

 incidentally by numerous authors, such as Bartram, Maclure, Conrad, 

 and Lyell, above mentioned, and by W. M. Carpenter, 1838; C. Peck, 

 1851, and C. G. Forshey, 1853; but R. Thomass/s "Geologie Pratique 

 de la Louisiane,^' 1860, with its supplement, 1863, is the first systematic 

 treatise on the topography and geology of the state. 



In March of 1869 the Louisiana State Geological and Topographic 

 Survey was inaugurated under the auspices of the State Seminary, sub- 

 sequently the Louisiana State University. The first explorations of Dr. 

 F. V. Hopkins, geologist, followed close on Hilgard^s reconnaissance, and 

 his first report for 1869 in like manner followed close on Hilgard's pre- 



