524 



Nekrologe von Antoine Cesar Becquerel und Henri Victor Regnault : 239. 

 0. C. Marsh: Notice of New Dinosaurian Reptiles: 241. 



April, Vol. XV, No. 88, p. 245—324. 



John J. Stevenson: On the Surface Geology of Southwest Pennsylvania, 

 and adjoining portions of Maryland and West-Virginia: 245. 



Jam. D. Dana: On the Driftless Interior of North America: 250. 



G. K. Gilbert: The ancient Outlet of Great Salt Lake: 256 



Frederick Prime jr.: On the discovery of Lower Silurian Fossils in Li- 

 mestone associated with Hydromica slates, and on other points in the 

 Geology of Lehigh and Northampton Counties, Easteren Pennsyl- 

 vania: 261. 



J. C. Russell: On the intrusive nature of Triassic Trap Sheets of New- 

 Jersey: 277. 



Dan. Kirkwood : On Croll's Hypothesis of the Origin of Solar and Sidereal 

 Heat: 291. 



J. W. Mallet: On the chemical composition of Guanajuatite, or Selenide 



of Bismuthe, from Guanajuato, Mexico : 294. 

 E. W. Claypole: On the occurrence of a tree-like fossil plant, Glyptoden- 



dron, in the Upper Silurian (Clinton) Rocks of Ohio: 302. 

 Roland D. Irving: Origin of the Driftless Region of the Northwest: 313. 

 Principal Dawson: The Earthquake of November 4, 1877: 321. 

 Obituary of Ch. Fr. Hartt and Angelo Secchi: 324. 



