492 W. TJpham — Quaternary Changes of Levels. 



trace of the influence of a deep-sea habitat. Hence the route may 

 have followed the coasts of Asia and Malaysia, in which case we 

 may hope for much further light to be thrown upon its progress by 

 collectors in that area ; or the line may have lain across what is 

 now occupied by the deep abysses of the Indian Ocean, but if so 

 it must have occurred before its bed had subsided to anything like 

 its present depth. 



EXPLANATION OF THE PLATES. 

 PLATE XIII. 



Figs. 1, 2, and 3. Cassidulus longianus, sp. nov., Willunga, S. Australia. Nat. size. 



Brit. Mus. E 3380. Fig. 1. Abactinal view. Fig. 2. Actinal 



view of another specimen. Fig. 3. Side view of former 



specimen. 

 Figs. 4, 5, and 6. Echinolampas pnsterocrassus, sp. nov., "Willunga. Nat. size. 



Brit. Mus. E 3381. Nat. size. Fig. 4. Side view. Fig. 5. 



Abactinal view. Fig. 6. Actinal view of same specimen. 

 Figs. 7 and 8. Echinolampas ovulum, Laube. Bairnsdale, Victoria. Brit. Mus. 



E 1107. Nat. size. Fig. 7. Actinal view. Fig. 8. Side 



view of same specimen. 



PLATE XIV. 

 Fig. 1. Pericosmus eompressus (Dune). "Willunga. Brit. Mus. E 3383. Half size. 

 Figs. 2 and 3. Cardiaster tertiarius, sp. nov. Willunga. Brit. Mus. E 3382. Nat. 



size. Fig. 2. Abactinal. Fig. 3. Side view of same specimen. 

 Figs. 4 and 5. Ccelopleurus paucituberculatus, sp. nov. Morgan, S. Australia. 



Fig. 4x2 dia. Fig. 5. Diagram of apical disc and surrounding 



plates x 4 dia. Ipswich Museum. 

 Figs. 6 and 7. Hemiaster planedechvis, sp. nov. Morgan, S. Australia. Nat. size. 



Ipswich Museum. 



T 



II. — Quaternary Changes of Levels. 

 By "Warren Upham, 

 of the United States Geological Survey. 



HE article by Prof. J. W. Spencer in the last May number 

 J_ of this Magazine brings together many evidences of high 

 continental elevation of North America preceding the Pleistocene or 

 Glacial period. Though Professor Spencer has not proceeded to 

 interpret these observations as revealing in continental elevation 

 the probable cause of the severely cold climate and accumulation of 

 ice-sheets during the Glacial period, I believe that this is a legitimate 

 conclusion, and that it strongly re-enforces the arguments long ago 

 advanced by Lyell and Dana, and recently emphasized anew by 

 Wallace. 



But certain other observations bearing on the length of the Post- 

 glacial or Eecent epoch lead me to differ from Wallace, who combines 

 high elevation with maximum eccentricity of the earth's orbit as 

 necessary concomitant conditions of glaciation. Closely accordant 

 computations of the length of Postglacial time have been reached 

 quite independently by Prof. N. H. Winchell, from the rate of 

 recession of the Falls of Saint Anthony ; l by Dr. E. Andrews, from 



1 Quart. Journ. Geol. Soc, vol. xxiv. 1878, pp. 886-901 ; Geology of Minnesota, 

 Fifth Annual Report, for 1876 ; and Final Beport, vol. ii. 1888, pp. 313-341, with 

 numerous plates and maps. 



