118 JOURNAL OF THE WASHINGTON ACADEMY OF SCIENCES VOL. 13, NO. 7 
de la Hotte, were not examined. The field work and most of the 
office work was done under the supervision of Dr. T. W. Vaughan of 
the United States Geological Survey. 
A complete report embodying the results of the reconnaissance, 
illustrated with many maps, diagrams, and photographs, has been 
prepared for publication, and it is intended to issue a French and an 
English edition. As this report will not be ready for distribution 
before the autumn of 1923, the following summary of the results of the 
reconnaissance is now published. 
GEOGRAPHY 
All the inhabitants of the Republic know that it is very mountainous. 
The only extensive plains are the North Plain, the Central Plain, the 
Artibonite Plain, and the Cul-de-Sac Plain. The Central Plain is 
the only large interior plain. The most important of the smaller 
plains are the Arcahaie Plain, the Léogane Plain, and the Cayes Plain. 
All of these plains, except the Central Plain, have played an important 
part in the agricultural development of the Republic. 
The Cul-de-Sac Plain is one of the most striking geographic features. 
It is part of a trough extending from Port-au-Prince Bay southeastward 
across the island to Neiba Bay and containing two lakes that have no 
outlet, Etang Saumatre in the Republic of Haiti, and Hoya de Enri- 
quillo in the Dominican Republic. It has been known for a long time 
that recently, geologically speaking, this trough was below sea level, 
dividing the island into two parts. 
Aside from these plains most of the Republic, except part of the 
Northwest Peninsula, is mountainous. The highest mountains are 
in the southern part of the Republic. Mt. La Selle, the highest peak 
according to available information, has an altitude of 2,680 meters 
above sea level, as determined by triangulation under the supervision 
of the United States Geological Survey. 
Contrary to the prevailing opinion the major geographic features 
are arranged in ares convex both northward and southward. Most 
of the ares trend northwestward. The geographic provinces, some 
of which have not heretofore been named, and their characteristic 
surface features are described in the final report. 
GEOLOGY 
Sedimentary rocks.—The oldest sedimentary rocks are schists 
that crop out on the North Plain and on Tortue Island. As these 
