Bulletin of Museum of Comparative Zoology 44

L_i, BULLETIN OF THE V , MUSEUM OF COMPARATIVE ZOOLOGY AT HARVARD COLLEGE, IN CAMBRIDGE VOL XLIV (Geological Series, VII.) CAMBRIDGE, MASS., 1901-1904 U S A V^j^t— 14 ^ University Press: John Wilson and Son, Cambkidge, U f :ro- S A Bulletin of the Museum of Comparative Zoology AT HARVARD COLLEGE Vol XLIV GEOLOGICAL SERIES, Vol, VIL THE STONE REEFS OF BRAZIL, THEIR GEOLOGICAL AND GEOGRAPHICAL RELATIONS, WITH A CHAPTER ON THE CORAL REEFS Bt John Casper Branner With Ninety-xine Plates CAMBRIDGE, MASS., U.S.A.: PRINTED FOR THE MUSEUM Ma\, 1904 The Stone Reefs of Brazil^ their Geological and Geographical Relations, ivith a Chapter on the Coral Reefs By John Casper Branner TABLE OF CONTENTS PAGE I II Introduction Sketch of the Geology of the Coast in its Relations to the Stone and Cokal Reefs Pre-Cretaceous The Cretaceous What is the age of tlie Bahia beds ? Conclusion regarding the Bahia beds The age of other coast sediments Tlie relation of color to age The Tertiary beds of the Amazonas The later Tertiary deposits Recent deposits Conclusions regarding the geology of the coast III Detailed Descriptions of the Sandstone Reefs Tlie Ceara stone reef The stone reef at Rio Grande Norte The Pirangy rock reef The stone reefs of the Cunhalm and Sibauma The Traipao stone reef The Mamanguape stone reef The consolidated beaches of Parahyba Norte The Pedra de Gale' or Goyanna stone reef The Rio Doce stone reef The Pernambuco stone reef The beach reef at Piedade The stone reef at Venda Grande, Pernambuco The Gaibu stone reef The stone reef south of Cabo Santo Agostinho The beach rocks at Porto de GaUinhas The Cacimba and Serinhaem stone reefs The stone reef of Santo Alei.xo The sandstone reef of Rio Formoso The stone reefs of the Rio Sapucahy, Alagoas The stone reefs of the Pratagy, Alagoas The stone reefs of Bahia The stone reef at Santa Cruz The stone reef of Porto Seguro Notes upon little-known stone reefs Miscellaneous localities VOL XLIV 8 9 11 13 18 25 27 31 32 34 34 35 40 40 45 47 55 56 59 60 67 68 69 71 78 79 80 81 88 91 93 95 97 99 101 bulletin: museum of comparative zoology PAGE regarding the Forms and Struct ore of the Stone Reefs IV Conclusions The shore beach Tlie off-shore beach Application to the Brazilian stone reefs Structure of the stone reefs Conclusions 104 105 105 107 108 110 V The Elevation and Depression of the Northeast Coast of Brazil Changes of the Ill reefs within historic times Observations of others Have there been changes within the historic period Conclusions Changes within recent geologic periods Views of former writers "^ The The schistose structure of the reef rocks dip of the reef rocks Reef rocks above high tide Lakes near the coast The fixed dunes of the coast Islands joined to the mainland The straightening of the coast-line Comparative effects of elevation and depression EfTects of elevation Effects of depression Forms on a stationary coast Application to Brazil Evidences of depression Ill Ill ? 114 117 118 118 119 119 120 121 121 122 124 125 125 125 127 127 127 128 Open bays Coast lakes Rios tapados 134 Choked embayments 137 Depressed valleys The case of Rio Sao Francisco Evidence of the islands 139 143 Off-shore clays Evidence of buried rock-channels Additional views of depression Evidences of elevation Elevated beaches, State of Alagoas Elevated beaches, State of Bahia Marine terrace at Ilheos, Bahia Lagoa de Itahype At Ponta d'Areia, Bahia At Victoria, Espirito Santo Elevated sea-urchin burrows The death and decay of the coral reefs Time relations of the elevations and depressions Influence of the coral reefs Influence of the mangues Hyacinths Origin of the coast sands 129 144 144 145 146 148 148 149 153 155 156 158 159 159 162 164 167 167 167 BRANNER: TFIE STONE REEFS OF BRAZIL PAGE Conclusions regarding coast changes VI 169 171 The Consolidatiox of the Stone Rekfs The cement 171 Analysis of rock from the stone reef of Hio Formoso The microscopic examination of thin sections of sandstone from the Rio Formoso reefs The origin of the cementing material Cement from the beach sands by rain-water or spray Lime carbonate from the ocean Carbon dioxide of submarine volcanic origin Carbon dioxide from sea-water, but not of eruptive origin 172 Is the process universal Lime carbonate from ? the land Tiie consolidated beaclies of the Levant Relations of density to deposition The seaward percolation of acid land-water Possible influence of climate The hardening process is not a continuous one Conclusions regarding the consolidation of the reefs VII 194 The Age of the Sandstone Reefs Stratigraphic relations Physiographic relations The fossils in the reefs Conclusions VIII Annotated Bibliography of the Stone Reefs of Brazil Re'sume' of the bibliography IX The Coral Reefs Local details The Rocas Cape St Roque reefs Lavandeira reefs Joao da Cunha reef Ceara reefs Fernando de Noronha The coral reef of Parahyba Norte Coral reefs between Parahyba and Recife The coral reefs from Pernambuco to Santo Aleixo Santo Aleixo The coral reefs between Santo Aleixo and Maceio Analysis of reef rock The Bahia reef Reefs between Itaparica and Caravellas Coral reefs off Caravellas The Abrolhos reefs Thickness of the coral reefs of Brazil The age of the coral reefs The chemical composition of Brazilian corals List of the corals of the coast of Brazil Notes on the corals collected By A W Greeley The Maceio coral reef Re'sume of conclusions regarding the coral reefs Explanation of the Plates 173 174 175 177 178 182 184 186 187 190 192 193 195 197 197 198 198 200 201 225 226 226 226 228 228 228 228 229 232 235 236 237 239 241 246 249 251 256 259 261 263 266 268 270 274 276 bulletin: museum of comparative zoology I Introduction There is no more striking geologic phenomenon along the eastern shores of South America than the stone reefs of Brazil These reefs are supposed by many persons to be of coral, and this error has been propagated by writers of books of travels and by works on the There are several reasons for this navigation of the south Atlantic error : many coral reefs border tropical coasts in a similar are extensive coral reefs on the coast of Brazil are unique, or rather they are found on a very limited scale ; nowhere manner ; there the stone reefs of Brazil else in the world except seen from a vessel sailing along the coast or ; even near at hand, the stone reefs are scarcely distinguishable from coral reefs even by an expert ; and, finally, the sandstone reefs are generally covered with calcareous growths only thing that is is common to coral reefs especially characteristic of the form and their straightness, this is not The of stone reefs always apparent to one looking at them either from the shore or from the ocean In Brazil the only men who really seem to know the dififereuce between the two kinds of reefs are the lime-burners who make lime of the corals, and a few of the masters of barca^as, or sugar boats is made between the coral rock, Among these which they know men rock), or as caber^a de carneiro (sheep's head, referring to oLher solid heads), and the sandstone which they that is, stone i.;sed for window and door sills distinction as j^edra de col (lime call Pontes and pedra de encantaria ; and facings, as the reef rocks have been used from the earliest times In a sense the sandstone reefs are local, but the forces and agencies that have formed them have been in operation along the entire coast, from near Maranhao to southern Bahia, while local conditions have prevented their formation at some places, or have favored their preservation or destruction at others The ports and towns behind the stone reefs owe everything to them Without these reefs there would be no Pernambuco, no Rio Grande Norte, no Porto Seguro, no Santa Cruz, to say nothing of the minor ports like Rio Formoso, Serinhaem, Suape, Traigao, Mamanguape, and BRANNER: THE STONE REEFS OF BRAZIL many others where the sugar boats load and take refuge along the whole coast from southern Bahia to Ceara The They — of sand are consolidated They stand about tide they are left a hard from a few paces in places almost like long, low, flat-topped walls, hundred and fifty with a width metres, and a length of to several kilometres They accompany tions from — flush with the water at high tide, while at lovv exposed of from five metres to one III to — sandstone quartzitic ir and Maranhao geological and geographical peculiarities of these stone reefs con- the facts that sist in I the shore line with many and north of Ceara to Porto Seguro, a distance of great interrup- two thousand kilometres With unimportant exceptions the IV reefs not occur along the Brazilian coast beyond these limits V They usually stand across the mouths of streams and estuaries forming perfect natural breakwaters for the small harbors behind them Sometimes they follow the shore, either on the beach distance from They VI or at a short it "When crooked, their curves are are all nearly straight gentle VII The structure and position of the they contain beach sands VIII reefs and the animal remains show that they have been made by the lithification of in place When stone and coral reefs occur together, the stone reefs are inside or landward of the coral reefs may It is possible, however, that there be buried coral reefs in some cases to the landward of some of the stone reefs The IX some coral reefs are now growing over and upon the stone reefs in places, while at other places there are stone reefs overlying dead coral reefs X In general appearance, elevation, and position the sandstone reefs bear a striking resemblance to the coral reefs My reefs was begun in 1875-6-7, while I was a member Commissao Geologica Brazil it was extended at subsequent visits in 1881-2-3, and ended in June, July, August, September, and October, 1899, when an opportunity was afl'orded me by Dr Alex- work on the of the ander Agassiz to finish ; it This last visit has been of the utmost importance, for I have thus been able to revise earlier and less trustAvorthy observations, to visit new localities, and also to study the prob- bulletin: museum of comparative zoology lems that present themselves after a more thoughtful consideration of the whole subject Like so many of the problems that at the outset, this anticipated years, I And even am more seem simple and one has turned out to be much easily disposed of than was less simple now, after having worked at it for twenty-five than ever impressed with the complexity, difficulty, and far-reaching nature of the problems surrounding these sandstone Above all, it seems evident that any satisfactory theoi'y of these reefs must include the study of the geographic development reefs — a study not hitherto attempted line, advanced of the coast- Certain theories that have been or in connection with these reefs are not in explanation of discussed in the present paper because they are without the bases that would entitle them One to serious consideration of their glacial origin.' It has already factory evidence of glacial of these is the theory been shown that there action in Brazil.^ Another is is no satis- the theory of the orographic relations of the reefs to the western Alps This idea was suggested to Liais by the once famous but now almost forgotten Systemes de Montagnes of Elie de Beaumont.* The problems world I of the coral reefs have long been before the scientific have not been able to undertake any comprehensive study of the coral reefs of Brazil, but I hope that this approaching of the subject may from the geological and geographical side these problems, In discussing the coral reefs my command and thro.v so far at least as this particular to I some coast is upon light concerned have endeavored to weigh the evidence at reach logical conclusions unbiassed by any particular theory There are several related topics which it was intended to discuss in connection with the ones here dealt with, such as the currents, winds, tides, submarine topography, and submarine erosion, but the paper is already too voluminous and those parts are omitted A great desideratum in studying the history of the Brazilian coast good topographic map This does not exist is a The hydi-ographic charts are the only ones available, but these deal only with such features as more interest navigators, while the maps than vague generalizations It is cause for congratulation that several of the interior are often of the Brazilian states imder the lead of Nouvelle geographie universelle du Sud, p 222 Sao Paulo, whose survey Par Reclus Tome XIX is Amerique Paris, 1894 Tlie supposed glaciation of Brazil L'Espace Celeste Par E Liais, p 762-763 little By J C p Branner, Journ Geol I, 544, 548 Comptes Rendus, p 753-772 1860 L., o < a w w a DQ Du f-> CK ^ * Du oc ca a CK CQ ... Coral reefs off Caravellas The Abrolhos reefs Thickness of the coral reefs of Brazil The age of the coral reefs The chemical composition of Brazilian corals List of the corals of the coast of Brazil... rocks were bulletin: museum of comparative zoology II Sketch of the Geology of the Coast in its Relations to the Stone and Coral Reefs PAGE Pre-Cretaceous The Cretaceous What is the age of the Bahia... ser 4, Jan and Feb., 1871, VII., p 59-64, 101-109 bulletin: museum of comparative zoology 26 and on the notes of Gabb's opinion of the age of the deposits Steere.^ he does not give correctly,