54 CONTENTS. 



I^eous rocks 86 



Geological structure 87 



The Lampasitas arch 88 



Minor folds 90 



Economic features 90 



Artesian water 90 



Water in cretaceous rocks 90 



Water from the tertiary rocks 92 



Waste of flowing water , 94 



Gas and oil 95 



Quantitative estimate 97 



Petroleum 98 



Probability of existence of oil 99 



Saltpeter 100 



Bat guano 101 



Conclusion 102 



