[Annals N. Y. Acad. Sci., Vol. XIV, No. 4, pp. 247-318, March 22, 1904. J 



THE GEOLOGY OF THE SAN JOSE DISTRICT, 

 TAMAULIPAS, MEXICO 



George I. Finlay 



(Read April 20, 1903) 



[Plates VIII-XVIII] 

 CONTENTS 



PAGE 



I. Introduction. Acknowledgments 248 



II. Topography. Drainage Features 249 



III. Stratigraphy and Structure 253 



I V. Stream Adjustment 254 



V. Field Relations of the Igneous Rocks 255 



VI. Petrography 257 



A. The Granitoid Types , 257 



1. Nephelite Syenite. General Description 260 



a. Baril Type 260 



b. Arroyo Grande Type 261 



c. Mesa Verde Type 263 



d. Mesa Verde Type, Basic Facies 264 



Analysis by Dr. H. S. Washington. Calculations 266 



2. Diorite 267 



Analysis. Calculations 268 



B. Porphyritic Types 269 



1. Andesite 270 



a. San Narciso Type 27Q 



b. Vegonia Type 272 



Analysis. Calculations 273; 



2. Dacite 273; 



a. Florencia Type 273. 



b. Imogenia Type 275. 



3. Basalt 277 



Analysis. Calculation 278 



C. Dike Rocks 278. 



I . Tinguaite 280. 



a. Santa Rita Type 280 



b. Iman Type 282 



Analysis. Calculations 282 



247 

 Annals N. Y. Acad. Sci., XIV, March 22, 1904 — 17. 



