div class=trans-pagebutton class=gotoPage data-page=1Page 1button div class=trans-imagea href=https:reader039fdocumentsusreader039viewer20220203175bb77c9409d3f2d32a8cfc1ehtml5page1jpg target=_blank img data-url=documentpubsusgsgov-las-tetas-lava-member-they-are-abundantly-porphyritic-and-thehtmlpage=1 data-page=1 class=trans-thumb lazyload alt=Page 1: pubsusgsgov · Las Tetas lava member They are abundantly porphyritic and the generally very finely crystalline groundmass is dark greenish gray in most exposures loading=lazy src=data:imagegifbase64iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mM8Uw8AAh0BTZud3BwAAAAASUVORK5CYII= data-src=https:reader039fdocumentsusreader039viewer20220203175bb77c9409d3f2d32a8cfc1ehtml5thumbnails1jpg width=140 height=200 adivdiv