E. S. Dana — Petrography of the Sandwich Islands. 441 



Art. XLYI. — Contributions to the Petrography of the Sand- 

 wich Islands; by Edward S. Dana. With Plate XI Y. 



The rock specimens, the" results of whose study are detailed 

 in the following pages, were in part collected by Professor James 

 D. Dana on his trip to the Sandwich Islands in August, 1887, 

 and the remainder by the Rev. E. P. Baker of Hilo in 1888. 

 The first series includes about thirty specimens from Kilauea, 

 a third of them from the projectile deposits on its borders ; 

 several from other points in Hawaii ; about a dozen specimens 

 from the island of Maui, chiefly from the extinct crater of 

 Haleakala ; and finally an equal number from different points 

 on the island of Oahu. The special localities are mentioned 

 beyond. The second series of specimens are all from Hawaii, 

 arid chiefly from Mokuaweoweo, the summit crater of Mauna 

 Loa. There are also a few specimens from Makaopuhi and 

 l^anawale on Hawaii, points which belong to the Kilauea 

 region. 



For our present knowledge of Hawaiian lavas we are in- 

 debted in the first place to the general descriptions of J. D. 

 Dana in the Geology of the Exploring Expedition (1849), 

 and W. T. Brigham in his Notes* on the Yolcanoes of the 

 Hawaiian Islands (1868); also C E. Dutton (1884) and others. 

 On the other hand, on the petrographical side, there have been 

 published the microscopic study of basaltic glass of Hawaii, 

 especially Pele's Hair, by Krukenbergf in 1877 ; a paper by 

 Cohen;}: devoted chiefly to the glassy basaltic lavas of Hawaii ; 

 brief descriptions of isolated specimens of nepheline basalts 

 believed to have come from Oahu by Wichmann§ and by 

 Posenbusch ;|| finally a recent memoir by Silvestri^f describing 

 a series of ancient and modern lavas from Kilauea collected 

 by Prof. Tacchini in 1883. 



1. lavas of Mauna Loa and its summit crater, Mokuaweoweo. 



Eor the collection of lava specimens from the summit crater 

 of Mauna Loa, the writer is indebted, as is stated above, to the 

 Pev. E. P. Baker.** The collection is a large one and evidently 



*Mem. Boston Soe. Nat. Hist., vol. i, pt. 3. 



f Mikrographie der Glasbasalte von Hawaii, petrographische TJntersuchung von 

 C. F. W. Krukenberg, Tubingen, 1877. 



JJahrb. Min., vol. ii, 23, 1880. 



§Jahrb. Min., 172, 1875. 



If Mass. Gesteine, 510, 1877. 



■[Bull. Com. Geol. d'ltalia, xix, 128-143, 168-196, 1888. 



** Mr. Baker's extended trip over Hawaii, which included, besides an explora- 

 tion of the summit crater, a visit to the sources of several of the great lava 

 streams, was undertaken in order to make the collections of rocks and gather 

 facts with regard to the eruptions, and some extracts from his notes are published 

 in this volume at p. 52. The results have proved to be of very great interest. 



