244 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
There are several apparently distinct localities and faunas in Brazil 
which have been called Cretaceous by different authorities. Тһе 
Cretaceous faunas described by Dr. C. A. White? are dissimilar to any 
other Cretaceous faunas of the continent, and G. D. Harris ? asserts that 
they are to all appearances equivalent to the midway stage of the Eocene 
Tertiary of the Southern Atlantic States. 
Hart and Hyatt have published contributions which undoubtedly 
show the existence of Cretaceous deposits in Eastern South America 
very closely allied to those of the Texas region.? 
The Marine Tertiary — Тһе marine Tertiary and Post-Tertiary sedi- 
ments of the Gulf Caribbean region, as well as of the Atlantic Coastal 
Plain of the United States, can all be placed in two broad physical cate- 
gories, to wit, formations composed of organically derived sea débris, 
and formations composed of land wash. 
Formations composed of Sea Débris. — The first class of Tertiary de- 
posits are chalky or brecciate white or whitish limestones, composed of 
sea débris, derived from the deposition or trituration of skeletal parts 
of marine organisms, and of calcareous matter from that which the sea 
rater holds in solution. 
These chalky or clastic limestones sometimes contain a small propor- 
tion of washed clay, and are always of whitish color. The clay has been 
thoroughly washed by long presence in the sea. An occasional particle 
of pyrites, supposedly an accompaniment of animal decay, may give by 
oxidation a faint yellowish or cream colored tinge to the rocks, but the 
darker browns and reds of the first mentioned category are conspicu- 
ously absent. Тһе white limestone formations have been made in the 
past ‘of bottom life and accumulations, or as can be seen in process of 
making to-day, by the wave and current broken and triturated shell and ` 
coral material, cemented by the lime derived therefrom. This class of 
lime formation may become, through interstitial alteration, irregularly 
indurated and partially crystalline, and, through solution, cavernous 
and porous. 
The white limestone formations are found in the Floridian peninsula, 
but especially abound in the insular areas of Tropical America through- 
out the Great Antilles, Yucatan, and the Bahamas. It is a singular fact 
1 C. A. White, Contributions to the Paleontology of Brazil, Rio de Janeiro, 1887. 
2G. D. Harris, Bull. of American Paleontology, No. 4, June 11, 1896. 
8 “Report on the Cretaceous Fossils from Maroim, Province of Sergipe, Brazil, in 
the Collection of Professor Hartt,” Geology and Physical History of Brazil, Hartt, 
Boston, 1870, р. 892. 
