950 Geological Society, 



2. ' Palaeontology of the Tertiary Deposits in North-Western 

 Peru.' By Henry Woods, M.A., F.R.S., T. Wayland Vaughan, 

 Ph.D., J. A. Cushman, Ph.D., and Prof . Herbert Leader Hawkins,, 

 D.Sc., F.G.S. 



3. ' Geology of the Quaternary Period on a Part of the Pacific 

 Coast of Peru.' By Thomas Owen Bosworth, D.Sc, M.A., F.G.S. 



Throughout the Quaternary Period, the littoral has undergone a 

 series of vertical oscillations. It has been lifted up and down 

 repeatedly like a lid, haying its edge a few miles out in the Pacific 

 Ocean and its hinge-line in the Andes. During these processes the 

 littoral has several times been alternately overspread with a marine 

 deposit and then raised above the sea. 



The ocean-soundings show a steep 2000-foot submarine cliff at 

 the edge of the continental shelf. It follows a fairly direct line, 

 which passes within 5 miles of the land. This cliff is taken to be 

 a submarine fault-scarp, marking the important fracture (Pacific 

 Fault) which was the western boundary of the Quaternary uplifts. 



The oldest and highest of the raised sea-floors ('tablazos') now 

 has an elevation of 1100 feet. It extends 20 miles inland, and,. 

 within the territory here discussed, it covers an area of 700 square 

 miles. The inland boundary of each ' tablazo ' is a raised sea-cliff. 

 The original western limit of each one of them probably was the- 

 edge of the continental shelf. Whether there was any oscillation 

 of the deep sea-floor on the west side of the Pacific Fault is not 

 known. The depth. 27 miles from the present coast, is 12,000 feet. 

 The Quaternary deposits formed upon it are presumably deep-sea 

 oozes. 



The events on the east side of the Pacific Fault may be grouped 

 into four similar episodes. Each consists of a subsidence accom- 

 panied by marine transgression, followed by an uplift causing 

 emergence of new land from the sea. They are as follows : — 



(1) The Maneora Episode, 



(2) The Talara Episode. 



(3) The Lobitos Episode. 



(4) The Salina Episode. 



Each episode obliterates all trace of any preceding one which 

 was not greater. Four episodes have left their mark ; but probably 

 there were many others, of which no evidence remains. 



The most substantial of the deposits formed during these marine 

 transgressions is 250 feet thick. The material ranges from shell- 

 limestone to beach-pebbles. The shells have been examined by 

 Col. A. J. Peile, who pronounces them (probably all) to be living 

 species. 



On the land, extensive breccia-fans and valley-terraces were pro- 

 duced, under desert conditions, during these oscillations. They 

 are correlated with the marine terraces. 



In conclusion, it is considered that not one ten-thousandth part 

 of the Quaternary history, here outlined, can have taken place 

 within the last 500 years. 



