230 BULLETIN : MUSEUM OF COMPARATIVE ZOOLOGY. 



(80) Between Cartago and Limon, Costa Rica. Hornstoue 1 Further 

 study required. 



(81) Between Cartago and Limon, Costa Rica. Hypersthene-andesite. 



(82) The summit between San Mateo and Boca, Costa Rica. A de- 

 composed trachytic lava with some fragments of similar lava, probably 

 not a water deposited tuff owing to the structure of the groundmass 

 which shows fluidal structure ; i. e. pyroclastic. 



(91) Guallavas. Fine grained gray rock ; a trachyte or trachytic 

 andesite. 



(92) Las Animas. Limestone tuff. Many fragments of plagioclase 

 feldspar, quartz (rare), basaltic rock, and pieces of shells, with a cal- 

 careous cement. 



(93) Above Las Animas. A scoriaceous dark gray enstatite-andesite, 

 or porphyrite, with a brown glassy base. 



(95) Las Animas. Limestone composed of fragments of shells with 

 a calcareous cement and rare grains of quartz or feldspar. 



(96) No. 13 Cliff. A gray limestone containing shell fragments. 

 One slide shows these fragments with a granular calcareous cement and a 

 rare grain of feldspar. The other has fragments of feldspar and basic 

 lava in abundance, with calcareous cement, and shows, indistinctly, 

 possible shell fragments. 



(97) Massive No. 13 Cliff. Theralite. Composed of green augite, 

 magnetite, biotite, olivine (serpentized) lathe-shaped triclinic feldspars, 

 apatite sodalite ; and zeolites representing the nepheline. 



(98) Guallava. Fine grained gray rock. One slide contains shell 

 fragments in a yellow calcareous cement. The other contains frag- 

 ments of feldspar ; calcitized bisilicates, basic lava in a calcareous 

 cement, but no recognizable shell fragments. 



(99) Venganza. Conglomerate of a dirty greenish gray color. The 

 fragments are basic lava and feldspar. 



(100) Pedro Fuego. Glassy basalt or augite-andesite. 



(101) No. 13 Cliff. A shell limestone with quartz and feldspar 

 fragments. 



(102) Ballast Cliff. Dirty green tuff, containing fragments of feld- 

 spar, calcitized minerals (hornblende, etc.), and fragments of andesitio 

 lava. 



(103) No. 15 Cliff. Sandstone with shell fragments, and quartz and 

 feldspar which suggest derivation from granitic rocks. 



(101) Same rock as 102. Ballast Cliff. 



(l"'l) Typical augite-hornblende-andesite. Type of a surface lava. 



