46 



SCIENCE, 



[Vol. VI., No. 128. 



THE LATEST VOLCANIC ERUPTION IN 

 THE UNITED STATES. 



In one of the volumes of the Proceedings 

 of the California academy of sciences, Dr. H. 

 W. Harkness describes the cinder-cone and 

 lava-field at Feather Lake, Plumas county, 

 Cal. Writing as I do in the field, and with- 

 out access to books, I am unable to cite more 

 accurately the description referred to. Dr. 

 Harkness speaks of this volcano as being ex- 

 tremely recent, and mentions the fact that 

 trees killed and half burned by the lava were 

 still standing. Mr. John B. Trask also refers 

 to it, with the statement that the eruption oc- 

 curred in January, 1850 ; but he does not, so 

 far as I recall, state the source of his infor- 

 mation. I regret that I am obliged to depend 

 upon memory alone in referring to these ac- 

 counts of the outbreak. Within the last week 

 I have had the pleasure of visiting Feather 

 Lake in company with Mr. J. S. Diller, and 

 can fully confirm Dr. Harkness's account of 

 it, and feel confident that Trask' s date, Janu- 

 ary, 1850, is quite in harmony with all appear- 

 ances. 



Feather Lake, prior to the eruption, was a 

 sheet of water about four or five miles long, 

 lying ten miles east-north-east of Lassen's 

 Peak, say, in latitude 40° 34^ and longitude 

 121° 19'; and its altitude is about 5,800 feet 

 above the sea. The vent now covered by a 

 large cinder-cone is situated a little above the 

 western shore. From it there fiowed a very 

 thick sheet of basaltic lava, which nearly filled 

 up the lake-basin. The thickness of the flow 

 considerably exceeds 100 feet, and may be as 

 great as 150 feet on the average. The lava- 

 field is about three miles and one-fourth in 

 length, and a mile in width, and half environs 

 the base of the cinder-cone. The cone itself 

 is nearly 600 feet high, and the diameter at 

 the base is about 3,300 feet. It is perfect in 

 form, with a crater in the summit which is not 

 broken down on an}- side. It is built of scoria 

 and lapilli, the outer layers of which are like 

 coarse sand, giving a smoothness and finish to 

 the surface of the cone which I have seldom 

 seen equalled. Great quantities of fine lapilli 

 and ' ashes ' are spread out over the adjoining 

 country to a distance of two miles, and over 

 the lava-sheet itself, quite burying it in some 

 places. The impression of recency is convej^ed 

 by ever}' aspect of the cone, of the lava-flow, 

 and of the country round about. The rains 

 have not, as yet, produced even the first trace 

 of a water-channel upon the wonderfully smooth 

 surface of the cone ; and the only vegetation 



which has taken root is a single bush of Cea- 

 nothus, near the summit. The lava-sheet is 

 rough and jagged in the extreme, but shows, 

 as 3^et, no trace of weathering. For a space 

 of four to five hundred yards from the cone, 

 the trees were all killed. Most of them have 

 fallen, and their decaj^ed trunks are still lying 

 on the ground, showing the marks of fire. In 

 thirty-five years (the period assigned by 

 Trask) such decay would be natural. Trees 

 of the same species, felled certainly since 1850, 

 show elsewhere in the vicinity an equally ad- 

 vanced stage of decay. 



Whether the date assigned by Trask be the 

 true one or not, the real date cannot be mate- 

 rially older. That the eruption was not at the 

 time a matter of common fame, is readily intel- 

 ligible ; for the settlement of the northern part 

 of the state did not begin until a year or two 

 afterwards, and it is not probable that any 

 observers except Indians could have witnessed 

 it. Harkness adds, I believe, that it was still 

 hot and feebty ' smoking' in 1852. This may 

 be quite true ; for the lava-sheet is an excep- 

 tionally thick one, and may have preserved its 

 heat for a long time. And it may also have 

 been seen by many white men in that year ; for 

 one of the routes by which overland emigrants 

 poured into the state was laid in that year 

 along the very base of the cone, and is known 

 to this day as the ' Emigrant trail.' 



I am not aware of any volcanic eruption in 

 the United States which is so recent as this 

 one. Vague accounts have been given of 

 eruptions in Oregon, Washington Territory, 

 and southern California within the last twenty 

 years ; but they have not been authenticated 

 or confirmed by subsequent observation of the 

 localities. There are lava-flows and cones in 

 Utah, Arizona, and New Mexico, and also in 

 southern California, whose ages must lie within 

 a very few hundred years, but not within the 

 present century. Unless something of the 

 kind more recent is found in some secluded 

 spot hitherto unvisited by the geologist, I 

 think we may safely regard the eruption at 

 Feather Lake as the most recent of any in the 

 countr}^ 



A word or two about the country in which 

 this volcano is situated. It is a volcanic region 

 of great extent, covering probably twelve thou- 

 sand square miles ; and Lassen's Peak is its 

 culminating point, and nearly its geographic 

 centre. It is thickly studded with great vol- 

 canic piles, and buried thousands of feet deep 

 in ancient lavas. Most of the eruptions are 

 of great antiquity, and those which built the 

 central pile of Lassen's itself are among the 



