T. A. Bendrat — Rocks of Cerro de Santa Ana. 269 



which is here designated as hornblende porphyry. On the 

 north side, however, W. Sievers states that the transition to 

 the porphyry occurs at an elevation of 450 feet. This horn- 



Fig. l. 



blende-porphyry, which weathers a brownish color, towers more 

 or less abruptly in bold cliffs up from the base of diabase, here 

 and there interrupted by short shoulders. It is considered by 

 the writer an intrusion into the diabase under such circumstances 

 as favored the formation of a porphyritic texture. This por- 



