112 FOUNDERS OF OCEANOGRAPHY 



at one time a bay of the Pacific Ocean, and that since 

 Cretaceous times it had been cut off from the Pacific by the 

 uprise of the Isthmus of Panama." 



This conclusion, it may be added, is in close agreement 

 with the later discoveries of geologists as to the movements of 

 land and sea in Central America. 



His later, and more specially oceanographic, expeditions 

 were primarily devoted to the exploration of coral reef 

 problems. After the death of his father, closely followed 

 by that of his young wife, in 1873, he spent much time in 

 travel abroad, and it was apparently during a visit to the 

 " ChaUenger " Office at Edinburgh, in 1876 or 1877 (when I, 

 then a young student of zoology, first saw him), that he 

 became interested in Murray's work on the building up and 

 the breaking down of calcareous deposits in tropical seas, 

 and especially in relation to the mode of formation of coral 

 reefs. The situation at that time, or at any rate the views 

 held at the " Challenger " Office and which excited Agassiz's 

 interest, are summarized in the following quotation from 

 Murray's obituary notice of his friend, pubhshed in the 

 Bulletin of the Museum of Comparative Zoology, vol. 54, 1911. 



I shall discuss the various theories as to the growth of 

 coral reefs and islands more fully in a later chapter, but this 

 wiU be sufficient to indicate the object and the bearing of 

 Agassiz's contributions to the subject as the result of his 

 many expeditions in coral seas. Murray says : — 



" One of the most striking results of the * Challenger ' 

 expedition was the discovery of enormous numbers of 

 pelagic calcareous Algae, pelagic Foraminifera, and pelagic 

 Mollusca in the surface and sub -surface waters everywhere 

 within tropical and sub -tropical regions, but the dead 

 calcareous shells of these pelagic organisms were not dis- 

 tributed with similar uniformity over the floor of the ocean. 

 In some places they formed pteropod and globigerina oozes, 

 but in the very greatest depths not a trace of these shells 

 could be found in the red clays which covered the bed of the 



