640 



SCIENCE. 



[N. S. Vol. IX. No. 227, 



them had seen charred -wood or bark in the holes. 

 Presumably charcoal was formed only where the lava 

 flow so completely covered the trees as to shut out the 

 air, and the pieces found had been eroded by the 

 Kalama River from wholly submerged molds." 



Mr. Coville's conclusion as to the forma- 

 tion of the charcoal is probably correct. 

 Mr. F. H. Knowlton, who studied the struc- 

 ture of the charcoal, recognizes the wood as 

 Douglas spruce (Pseudotsugamueronata). At- 

 tention was called {Nat. Geog. Hag., Vol. 

 VIII., p. 226) several years ago to the tree 

 molds or tree wells by Captain P. Elliott. 

 Through Mr. J. H. West, of Woodland, 

 Washington, Mr. F. A. Walpole, one of Mr. 

 Coville's assistants, secured a piece of the 

 basaltic lava from one of these tree molds 

 three feet in diameter. The piece of lava 

 shows the impressions of the bark in 

 great detail. In the hope of obtain- 

 ing some evidence concerning the age 

 of the lava flow associated with the tree 

 molds and charcoal I entered into corre- 

 spondence with Mr. West, who reports 

 charred logs at least forty yards up the 

 slope from the high-water mark of Kalama 

 River. One of the charred logs is twenty- 

 eight inches in diameter, and some of them 

 are partly woody, not having been com- 

 pletely converted into charcoal. Near the 

 Eiver at one point the charred logs are found 

 under six feet of sand and gravel, on which 

 are now growing fir trees having a diameter 

 of three feet. Some of the charred logs, 

 therefore, appear to be at least 100 years old, 

 for a fir three feet in diameter would prob- 

 ably require at least that length of time to 

 attain its present size. If this be true it is 

 probable that some of the charred logs are 

 not the result of the last eruption of St. 

 Helens, but of an earlier one. There is 

 historical evidence furnished by Fremont 

 (Memoirs, p. 282) to the efi"ect that Mt. St. 

 Helens and also Mt. Baker were in eruption 

 November 23, 1843. At that time a light 

 fall of ashes occurred at the Dalles, Oregon, 



on the Columbia, fifty miles from Mt. St. 

 Helens, which was then noted as being in a 

 state of eruption. Rev. Mr. Brewer collected 

 some of the ashes and gave them to General 

 Fremont, who visited the Dalles a year later. 

 Mt. Baker is thought to have been in erup- 

 tion at the same time, aild tlie natives re- 

 port that the fish in the Skagit River wer& 

 killed by its ashes. Mr. S. F. Emmons gives- 

 (Jour, of the Am. Geog. Soe., Vol. IX., p. 53) 

 the testimony of a former Hudson Bay 

 trader who saw an eruption of Mt. St. 

 Helens in the winter of 1841-2. 



It is hoped that the question may be settled 

 sometime in the near future by a geological 

 survey of both Mt. St. Helens and Mt. 

 Baker. While it may not be possible to es- 

 tablish the date exactly, the geological re- 

 cords upon the mountain slope are likely to 

 be such as to give the relative age with cer- 

 tainty. The case of the cinder cone, ten 

 miles northeast of Lassen Peak, California, 

 may be noted as an example of the results 

 of investigation in the field. Professor 

 Harkness was of the opinion that the erup- 

 tion occurred in January, 1850. The fresh- 

 ness of the material was so striking that 

 Major Dutton and I, who visited the region 

 in 1885, were at first of the same opinion, 

 but fuller investigation, an account of which 

 is published in the U. S. Geological Survey 

 Bulletin No. 79, shows conclusively that 

 the explosive eruption from the cinder cone 

 must have occurred long before the begin- 

 ning of the present century. 



J. S. DiLLEE. 



U. S. Geological Survey, 

 Washington, D. C, April 23, 1899. 



TBE PROSPECTIVE PLACE OF THE SO LAB 

 AZniUTS TABLES IN THE PROBLEM 

 OF ACCELERATING OCEAN 

 TRANSIT. 

 It is not generally recognized that science, 

 employing the mathematician and the engi- 

 neer alike in the problem of shortening the 

 duration of ocean transit, has accomplished 



