TYPICAL SECTIONS OF THE JURASSIC 645 



sections, are characterized by rounded edges, holes through the blocks, 

 and channeled surfaces frequently traversed by veins of calcite. This 

 part of the series is the most highly fossiliferous, containing ammonites 

 of Kimmeridgian and Portlandian affinities. A loose block, found on 

 one of the mountain sides, but of the same lithic character as these strata, 

 contained a specimen of Kossmatia victoris Burckhardt of Portlandian 

 age. Unidentifiable echinoderm plates were also found in these beds, 

 which increase westward to a thickness of about 500 feet in the region 

 of Consolacio, where the lower members contain Kimmeridgian fossils. 

 The top of the Jurassic section is formed of sheer cliffs of hard gray 

 and gray-black, thin-bedded limestones interbedded with thin seams 

 of brownish shale, which weather white. Some iron is disseminated 

 through the strata and there are occasional lenses of chalcedony. In 

 Morichi Cave, to the east of the Eio Hondo, echinoderm plates were 

 found in these rocks. On a hillside loose, weathered, yellowish-colored 

 blocks were found containing Haploceras and what appears to be a 

 small species of Hamites. The total thickness of the Jurassic in this 

 region is not over 375 feet and is in marked contrast to the much greater 

 development in the Viiiales sections to the west. 



/S'J.V CRISTOBAL SECTIONS 



Seven miles north of San Cristobal are the headwaters of a small 

 stream, the Eio San Cristobal, parallel to and east of which flows the 

 Eio Hondo. In these stream beds are exposed black shales of Lusitanian 

 and Kimmeridgian age (figure 2). Near the town of Eio Hondo and 

 northward along the banks of the stream of that name the rocks of the 

 uppermost Jurassic are visible. They are the same limestones with inter- 

 calated shales which form the outcrops north of Candelaria. The shales, 

 which Weather white or fawn-colored, contain aptychi which may be of 

 late Tithonian age, but which more closely resemble Lower Cretaceous 

 species. 17 They are found in outcrops northeast of Mount Pimiento, 

 an igneous peak lying to the west of the Eio Hondo, and also on the 

 Pinca of Rafael Begoa, 9 miles north of San Cristobal. At Morichi and 

 at Paradon Sariego, northwest of Mount Pimiento, these strata present 

 vertical cliffs nearly 200 feet in height with the bedding planes in their, 

 original condition. The summit of the high mountain north of San 

 Cristobal, known as Peha Blanca, is completely covered by these white 

 limestones. Within the range of the mountains they appear as bold, 



17 Marjorie O'Connell : New species of ammonite opereula from tbe Mesozoic rocks of 

 Cuba. American Museum Novitates, No. 28, 1921, 15 pp.. IS text figures. 



