132 
Transactions Texas Academy of Science. 
188. Hay, Eobert. 
Final Greological Eeports of the Artesian and Underflow Investi- 
gation beltween the fSTinety-seventh Meridian of Longitude and the 
Foothills of the Eoeky Mountains to the Secretary of Agricnltnre. 
Part III, of Senate Executive Document Uo. 41, of the 1st 
‘Session of the 52d Congress. Washington, 1892. 
Letter of Transmittal. Contents: General Report, Plan of Work. 
Geology of the Plains: Water-holding Rocks; Reconnaisisanoes in Mon- 
tana and Wyoming. Topography of the Plains: Increment of Elevation 
Westward; Rivers separated into two Classes as to their Source, Mountain 
Rivers and Plain Rivers; Western Escarpment of the Plains. Water 
Supply of the Plains: Rivers of the Plains; Origin of their Waters; Spe- 
cial Description of the Smoky-Republican Region^ Wells in the Interfluvial 
Spaces ; Measured Flow of some of the Rivers of North Dakota : Classifi- 
cation of Artesian Wells by Depth and Pressure; The Red River Region, 
its Low Altitude and Smooth Contour; Character of the Water in the 
Wells; Extension of Artesian Areas discussed; Geoloigy of the Glaciated 
Area; The Turtle Mountains; Variation of Lake Levels. The Underflow: 
iCommon use of the Ternrs in the West; The Facts of the Underflow; 
Restriction of the Term to its proper Range. Artesian Wells; Increased 
Numiber of Wells in the Principal Basins; Sources of 'Supply 'of the 
Dakota Alain Basin; General 'Conditions of Artesian Flow; Other Causes 
of Flow besides Hydrostatic Pressure. 
Reference is made to Texas under ‘The Lnderflow” and “Artesian Wells.” 
189. 
The Artesian Underflow Investigation. 
iCorrespondence. 
Amer. Greolo'gisit, Vel. XI, pp. 278-279. Minneapolis, Apr., 
1893. 
The reply to a criticism (Amer. Geol., Vol. XT, p. 113) of the “Final 
Geological Report[s] of the Artesian and Underground [Underflow] inves- 
tigation, between the iNinety-, seventh Meridian of Longitude and the Foot- 
hills of the Rocky Alountains to the Secretary of Agriculture. Made by 
Prof. Robt. Hay, F. G. (S. A., Part Third, Washington, 1892.” 
190. Heilprin, Angelo. 
The Eocene Mollnsea of the State of Texas. 
FrO'Ceedings Acad. Xat. Sciences, Phila., Ft. Ill, pp. 393-406; 
plate xi. Oct. -Dec., 1890. 
“The following list embraces, so far as :I know, all the Eocene Mollusca 
that have thus far been noted to occur in the Gulf deposits of the State 
of Texas. For my data I have used the type series of Gabb and Conrad, 
the major portion of which is in the possession of the Academy of Natural 
'Sciences of Philadelphia, the extensive oollection of the 'State Geological 
Survey,, and minor collections which have from time to time reached the 
Academy and been reported upon in its publications. The collections of 
