on the east by some 50 feet of bedded basaltic tuffs v35.37 v24.40 overlain opposite the island by clear shale interbedded with tuff seams 6 or 7 feet of these shales outcrop v40.37 = 5.35.7 containing A Balvanella abundant Choustra bastini common Steroschema " pulchra + lacunosa " Nunclersonia Similar shales with the same fauna 5.35.7.A outcrop in the west side of the islands off the shore The main mass of these islands is composed of a very coarse reddish argillite tuff massive. Both tuffs & shales are cut in the east & west by trap 5.35.7A2 (not coll.)