GEOLOGY AND PALEONTOLOGY OF THE CANAL ZONE. 601 



5. Yucatan. — This province consists of lowlands, under 600 meters 

 in height, underlain by only slightly deformed Tertiary strata, except 

 some problematic rocks west of Belize. The Yucatan Peninsula and 

 Campeche Bank are comparable to the Floridian Plateau. They are 

 developed along a structural axis almost at right angles to the con- 

 tinental trend. Campeche Bank projects northward from the shore 

 line of the peninsula 170 nautical miles to the 100-fathom curve and 

 has a width of nearly 360 nautical miles along an east and west line. 

 On the east the depth of water between it and Cuba exceeds 1,000 

 fathoms and the axial trends are not coincident, but the axis of 

 Yucatan Bank and that of the Province of Pinar del Rio, Cuba, curve 

 so that they are nearly parallel, with a trough, Yucatan Channel, 

 between them. 



6. Guatemala- Cliiapas. — This province lies between the Yucatan 

 lowland on the north and Rio Motagua on the south. It is an up- 

 land dominated by east and west tectonic lines, and has been called 

 the Guatemala-Chiapas Plateau by Tower. 1 



7. Cuba. — This province is coincident with Cuba and its submarine 

 continuation, the Cayman Ridge. At least four subdivisions should 

 be recognized: (1) The Isle of Pines, which is composed of mountains 

 of schists and marbles with piedmont plains and marsh, separated 

 from the main island by water less than 10 fathoms deep. (2) 

 Organos Mountains of Pinar del Rio and the accompanying piedmont 

 plains. The 1,000-fathom curve is less than 20 miles off the north 

 shore. (3) Central Cuba, from the east end of Organos Mountains 

 to Cauto River, is mostly a plain broken by some hills of serpentino 

 and granite, and in Santa Clara Province, near Trinidad, mountains 

 reported to be composed of Paleozoic sediments attain an altitude 

 of about 2,000 feet. (4) Sierra Maestra and Cayman Ridge. Thi3 

 subprovinco lies between the Cauto Valley and the south shore and 

 is continued westward as the submarine Cayman Ridge, along the 

 axis of which only the Cayman Islands project above water level. 

 The axial trend is nearly east and west between Cabo Cruz, Cuba, and 

 Little Cayman, whence it curves to the southwest and pitches toward 

 the head of the Gulf of Honduras, which is an area of depression. 

 Between the Caymans and the Isle of Pines the depth of water exceeds 

 1,000 fathoms, while the Bartlett deep to the south, separating Cuba 

 and Jamaica, exceeds 3,000 fathoms in depth. 



la. Haiti, northern fart. — The island of Haiti lies at the conver- 

 gence of the trend of the axis of the central subprovince of Cuba and 

 the Honduran-Jamaican axis. The dividing line in Haiti is from 

 Port au Prince to Ocoa Bay. t The area south of this line belongs to 

 a Jamaican axis, while that to the north belongs to the central 



i Tower, W. L., Investigation of evolution in chrysomelid beetles of the genus Leptinotarsa, Carnegie 

 Inst. Washington Pub. No. 48, p. 50, 1906. 



