Vol. XXVII. 

 1910 



] Armitagb, Plant Rejfiains in Olivine-Basalt. 23 



In connection with a peculiar quartz-basalt lava flow, which is 

 thought to have occurred about one hundred years before the 

 American Revolution, near Volcanic Ridge, which connects the 

 northern end of the Sierra Nevada in California with the Coast 

 Range, Mr. Diller (6) writes : — " Plate xiv. shows the upper 

 portions of a tree projecting from beneath the lava. The top 

 has been broken off and lies upon the ground. The tree was 

 pushed over by the advancing lava, and apparently belongs to 

 those killed at the first eruption when the Cinder Cone was 

 formed. ... As the stumps of the trees killed at the 

 time of the earliest eruption decay, the sand caves in to take the 

 place of the wood and forms a pit, as illustrated in the figure. 

 These pits, often three feet deep, are numerous near the base of the 

 Cinder Cone, and may be observed at least to the south-west for 

 a distance of one and a half miles from the cone." 



This last description coincides to some extent with that of the 

 Kilauea eruption, as well as with the descriptions of the 1865 

 Etna eruption and that in North Celebes. In all of these cases, 

 which are geologically very recent, it is most probable that the 

 plant remains referred to will become unrecognizable as such 

 before the lapse of any great geological time. 



Mr. Seward (7), speaking of plant remains associated with the 

 action of volcanoes in Upper Palaeozoic times, says : — " It is 

 well known to geologists that during the Permian and Carbon- 

 iferous periods the southern portion of Scotland was a scene of 

 widespread volcanic activity. Forests were overwhelmed by lava 

 streams or showers of ash, and, in some districts, tree-stems and 

 broken plant fragments became sealed up in a volcanic matrix." 

 " On the coast near Burntisland, on the Firth of Forth, 

 blocks of rock are met with in which numerous plant fragments 

 of Carboniferous age are scattered in a confused mass through a 

 calcareous volcanic matrix. The twigs, leaves, spores, and other 

 portions, are in small fragments, and their delicate cells are often 

 preserved in wonderful perfection." It will be noted that Mr. 

 Seward makes no mention of plants being found actually sealed 

 up in an igneous rock, his references being rather to plant remains 

 found under lavas or in pyroclastic tuffs. 



In 181 9, Dr. Macculloch (8), in portion of his description of the 

 geology of the island of Mull, wrote : — " The last substance which 

 it is necessary to notice as occurring in this trap, is carbonized wood. 

 This substance is contained in a perpendicular vein, about fifty 

 feet in height, and five feet in breadth .... the upper (end) 

 terminating abruptly in the mixture of solid and columnar basalt 

 by which it is everywhere surrounded. The upper part of this 

 vein is a conglomerate of soft grey trap fragments imbedded in a 

 paste of the same material. Toward the bottom it varies and 

 becomes mixed with a black substance, which on examination is 

 found to consist of minute fragments and a fine powder of car- 



