447 Dominican Sections — Maury 31 



our visiting the Nivaje and Upper Yaqui but we hope to do so 

 later. Our collections and sections from the regions farther west 

 however sufficiently indicate that all blue clays are not alike in 

 age. They are not a unit, but one set, represented by Zones 

 A-F and Bluff 1, occurs above the Tertiary gravel, and another 

 set, represented by lower H and G and Bluffs 2 and 3, occurs 

 with and below the Tertiary gravels. It remains to be proven 

 in the field whether the true "Nivaje shale" goes with the upper 

 or the lower set. 



Tertiary and Quaternary Oscillations of Level - 



The alternation of Tertiary gravel with clays as shown in 

 our Sabaneta and Cana sections indicates alternate elevations and 

 depressions of the shore line. 



Terraces furnish another indication of changes of level. The 

 high level terraces seen from the bluff at Hato Vie jo on the Mao, 

 plate 2B, have been described on page 8, Bulletin 29. 



A striking indication of rather recent uplift is 'the rejuvena- 

 tion of the Rio Cana described on page 9 of that bulletin. 



Gabb* gives an interesting account of the raised sea caves in 

 the Post Pliocene coastal limestone, in one of which he made his 

 camp, and he remarks that they prove the recent, "and yet con- 

 tinuing, ' ' uplifting of the land. I saw a great many sea caves 

 in process of formation on passing around the eastern and south- 

 eastern part of Santo Domingo and was informed that on the 

 small, uninhabited Island of Saona there are two level sea caves. 



These indications of uplift accord with those recorded by 

 the raised coral reefs of Jamaica noted by Hill, and those of the 

 Brazilian coast studied by Branner. Similar changes have also 

 been noted in Porto Rico. 



Geology of El Morro de Monte Cristi 

 The location of the Morro is shown on the Sketch Map, fac- 



*Trans. Amer. Phil. Soc, vol. 15, p. 146, 1873. 



