44 PROCEEDINGS OF THE ALBANY MEETING 



mitted, while at the same time giving scientific discussion full swing in its 

 proper place. . . . The volume is thus divided nearly evenly between a 

 'geological' and an 'agricultural' portion ; the former giving, under the special 

 heading of 'useful materials,' the technically important features of each forma- 

 tion, after its geological characters have been discussed." 



This report is one of the classics in its line, as, barring details since 

 worked ont and outlines since filled in, it presents the geology of Missis- 

 sippi practically as it is known at the present day. With Tnomey's re- 

 ports of Alabama and Safford's of Tennessee, Hilgard's stands easily in 

 the liighest rank of the State reports of that day and time, or, for that 

 matter, of any time. 



The data for his I'eport on the exceptional character of the Mississippi 

 River delta and for liis geological reconnaissance of Louisiana Avere 

 obtained by him on a trip down the Mississippi Eiver to the passes, made 

 under the auspices of the Smithsonian Institution in 186T, and on an- 

 other trip in 1869 across the State of Louisiana under the auspices of 

 the 'New Orleans Academy of Sciences and the Bureau of Immigration 

 of the State of Louisiana. The combined results of these trips and of 

 liis previous Mississippi emljayment studies have Ijeen summarized by him 

 as follows : 



"1. The outlining of the Mississippi embayment in Louisiana and Mississippi. 



"2. The outline geological study and mapping of these States. 



"3. The recognition of the Cretaceous ridge or backbone of Louisiana, from 

 Lake Bistineau to the chain of Salt Islands, and the determination (inferen- 

 tial) of the Cretaceous age of the rock-salt and sulphur deposits of Calcasieu 

 I'arish. 



"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 Hud- 

 son formation." 



In his Mississippi geological work, referred to under section 2 above, 

 lie was the first to give a clear and definite account of the origin and 

 distribution of the surface formation Avhich he called Orange Sand, but 

 which later, by agreement, received the name Lafayette. While some 

 ([uestion has arisen during the last few years 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 much of the area of the Gulf 

 Coastal Plain, by whatever najne it l)e called, and as to the general mode 

 of its accumulation. 



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. 



