A GEOLOGICAL RECONNAISSANCE IN HAITI 751 
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Between the Cul-de-Sac depression and Ville Bonheur (Saut 
d’Eau) is a well-defined crater from which extend basalt flows. 
These flows occupy depressions in the present topography and have 
not been since modified by erosion other than the removal of fine 
loose material leaving along the edges of the flows loose blocks of the 
volcanic rock resting on underlying formations. These rocks are 
very recent and were poured out during one of the last eruptions in 
Haiti. 
Deposits of volcanic ash occur at numerous places, and it is 
said that one or more cinder cones are located near the coast on the 
south side of the north peninsula. 
GEOLOGIC STRUCTURE 
The structure sections shown herewith are composite sections 
based on Tippenhauer’s work and the writer’s observations. The 
profiles are only generally correct. The sections covering the south 
peninsula are based on Tippenhauer’s mapping with certain modi- 
fications of his interpretations. While the writer has crossed this 
peninsula in two places his trips were very hurried and the thick 
vegetation prevented him from taking more than very casual notes. 
From the Cul-de-Sac plain north to the foothills of the north range 
the section is largely the writer’s, especially the part covering the 
central plain. The several sections across the plain are the writer’s 
and the section across the north range is somewhat imaginary, 
though it does illustrate conditions in that region. The last part 
of the section is in Santo Domingo across the Yaqui Valley and the 
Monti Cristi Range and is generalized. It is inserted to show 
the relationships of the Oligocene-Miocene formations there to the 
equivalent formations of the central plain of Haiti. 
The structure across the central plain region shows generally 
sharp flexing of the Oligocene-Miocene series along the western side 
of the plain, while the underlying limestones are generally faulted 
by thrust faults of some displacement. The sharp flexures in the 
later sediments are doubtless faults in the limestone beneath. A 
large fault is indicated well up on the south range of Haiti, a well- 
marked depression extending east and west along the course of this 
fault. 
