Fenton — Physiography and Glacial Geology of S. Patagonia. 221 



genial climate, the surface of the land had everywhere been cut into by large 

 river-valleys, with many tributary caiiadones. During the genial period 

 which followed the retreat of this great ice-mass, volcanoes began to break 

 out, some pouring out their lava on the surface of the first pampa level, 

 others in the great, broad river-valleys. During all this time the country 

 was slowly rising, and, after a certain interval, which it is impossible at 

 present to determine, the climate once more began to get cold, and the ice 

 began to creep down from the mountains into the plains. 



This sequence of events was probably repeated from time to time right 

 through the quaternary era, and, although I have only succeeded in finding 

 four moraines attributable to different horizons, I have reason to believe that 

 the changes mentioned above occurred at least seven times, and in this 

 connexion it is worthy of note, as I will presently explain, that the last 

 moraine found, although of the small valley type, extended practically as far 

 towards the east as the great plateau one first mentioned. 



APPENDIX. 



On the 28th March, 1915, I left Estancia Alquinta and proceeded to 

 Douglas (Esperanza), on the north side of the Gallegos river, my intention 

 being to stirdy the line of junction between the great terminal moraine and 

 the flat pampa, which I had good reason to believe existed between these 

 two points. After two and a half hours I noticed on going up to the 

 higher level that the pampas had still all the characteristic flatness already 

 described as universally found to the north of the Gallegos river. Here I 

 found myself at the foot of a long, stiff incline, which I ascended, and on the 

 top of which I halted to rest my horse. I here quote from my notes written 

 on the spot : — " 28th March. 2 p.m. Rode from Alquinta to Douglas ; 

 after entering Bella Vista camp had a long pull up to the top of a pampa. 

 Here the barometer registered five hundred and thirty feet above Alquinta. 

 Could see from this point the change from the flat pampas to the undula- 

 tory. There is no very marked rise of level, but the undulatory condition 

 of the surface of the high pampa can be distinctly seen. Mouth of Gallegos 

 Chico from here bore S. by E. magnetic. The pampas have what might be 

 called a drumlin appearance. The line of demarcation between the flat and 



SCIENT. PEOC. K.D.S., VOL. XVI, NO. XIX. 2 I 



