Scientific Survey of Porto Rico and the Virgin Islands, Volume 1

New York Academy of Sciences, 1922 - Puerto Rico - 12 pages

Geological reconnaissance	14

Diorite porphyry sills 55N8 9999 2860 997	20

Problems of the Survey	24

Bibliography	29

New Base Map of Porto Rico By CHESTER A REEDS	30

Valley of the Plata just below the power dam at K 19 Comerio Road	39

San Juan consolidated dune sand forming fringing islands at Vega Baja	43

The inner lowland and the inface of the cuesta at Corozal	49

Biotite granodiorite	187

Porodiscus concentricus in tuffaceous shale	195

Vulcanism	202

Chlorite developing from feldspars which are associated with fresh augites	203

Mineralization	209

Coamo Springs	210

Barrio del Carmen Prospect	221

Geology of the Ponce District By GRAHAM J MITCHELL	229

Exfoliation producing concentric arrangements in ash beds south	62

Typical foraminiferal shale	68

Igneous Rocks	76

Diorite porphyry sills intruded between layers of shales and ashes at K	77

Soda granite showing poikilitic structure	83

An andesite porphyry with large phenocrysts of plagioclase surrounded	89

Diorite porphyry with pyroxene phenocrysts in a groundmass of lath	91

Structural Features	95

Crossbedded structure in the San Juan formation at Arecibo	97

Mineral Occurrences	102

Geology of the CoamoGuayama District By EDWIN T HODGE	111

BY EDWIN T HODGE	112

Block diagram of Coastal Plain	117

Tuff beds	131

Character of the unconformity between the BarranquitasCayey and	138

Ash shales containing Orbitolites	144

Lithic tuff	151

Coamo Springs Range	157

Shales of the Rio Descalabrados series	163

Cerro Gavias Coastal Terrace Coamo River	169

Augite andesite showing feldspars completely altered augites unaltered	175

Lava flow containing pyroclasts of calcite which are surrounded by garnets	181

Portion of Complex mountain province as seen from the Tertiary hills	235

Cuspated beach west coast Porto Rico just south of Melones Point	246

Fluted Guayabal limestone of Juana Diaz	256

Rio Yauco shale as seen from point one mile north of kilometer 15	262

Augite porphyrite showing zoned augite crystal set in finegrained ground	274

Clypeaster rosaceus Lamark	284

Montalva Salina west of Guanica on south coast	296

The Physiography of Porto Rico By ARMIN K LOBECK	301

Map showing the average annual rainfall in Porto Rico	303

Block diagram of the southwest corner of Porto Rico	311

The valley and flood plain of the Rio Grande de Loiza near Carolina	317

The inner lowland at Guanica	321

The gorge of the Manati incised below the surface of the coastal plain	330

Apparent wavecut bench at Quebradillas	336

Road cut at K9 H 9 on the PoncePeñuelas road showing relation of Ter	342

Lower course of the Descalabrado River during the dry season	350

Tidal flats just east of Point Embacaderos	351

The Caribes Islands	357

The coast east of Quebradillas	365

East coast of Mona Island	372

Index	381

Geologic Map of the San Juan District Porto Rico	383

Title	Scientific Survey of Porto Rico and the Virgin Islands, Volume 1 Scientific Survey of Porto Rico and the Virgin Islands, New York Academy of Sciences
Author	New York Academy of Sciences
Publisher	New York Academy of Sciences, 1922
Original from	Princeton University
Digitized	31 Mar 2010
Length	12 pages

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