626 



SCIENCE 



[N. S. Vol. XXV. No. 642 



inated one of the original species from tlie old 

 genus must be considered as a first reviser, 

 since he thereby restricted the limits of the 

 old genus. In like manner the author that 

 subsequently eliminated one of the species 

 from the restricted genus must also be consid- 

 ered a first reviser, and so on down the line. 

 Where the old genus originally contained only 

 two species, neither of which had been desig- 

 nated its type at the time the first reviser 

 eliminated one of them as the type of a new 

 genus, he thereby caused the remaining spe- 

 cies to become, by elimination, the type of the 

 old genus, although he did not so designate it. 

 Elimination, therefore, instead of being in op- 

 position to, is in reality a part of the first re- 

 viser method. 



The action of the first reviser has been up- 

 held by the botanists as well as by zoologists, 

 and is in perfect accord with the fundamental 

 law of priority. Its very reasonableness has 

 commended it to practically all workers in 

 every department of natural history. On the 

 contrary, the first species rule demands that 

 the action of the first reviser be nullified in 

 all those cases where he had designated any 

 other than the first species as the type of the 

 old genus, or had taken the first species as the 

 type of a new genus; it is, therefore, in direct 

 opposition to the first reviser method plus 

 elimination, and also is in opposition to the 

 law of priority. The futility of attempting to 

 force this unreasonable, non-scientific method 

 upon thoughtful, reasoning workers would ap- 

 pear to be so self-evident as to require no 

 further comment. D. W. Coquillett 



U. S. National ircsExiM, 

 April 3, 1907 



POLISHED PEBBLES 



To THE Editor op Science : On page 392, in 

 the issue of Science for March 8, 1907, it is 

 stated that wind-polished pebbles from New 

 Jersey are facetted. The wording of the asser- 

 tion is such as to justify the possible inference 

 that wind-polished pebbles are always facetted. 

 It is doubtless true that in regions where the 

 wind is prevailingly from one quarter, pebbles 

 partially imbedded and held firmly during the 



polishing process, are usually facetted. On 

 the other hand, where hard imimbedded peb- 

 bles and boulderlets lie on the surface of hard 

 rock ledges, fully exposed to strong winds, they 

 become highly polished, but seldom or never 

 show even the slightest tendency to facetting. 

 Facetting can not, therefore, be regarded as 

 an unfailing characteristic of wind-polished 

 pebbles. At White Rock, a few miles east of 

 Boulder, Colo., beautifully polished quartz, 

 quartzite and other pebbles lie by thousands 

 on the wind-eroded surface of the Laramie 

 and Fox Hills sandstones, but probably a day's 

 search would not secure a single pebble show- 

 ing the slightest suggestion of facetting. A 

 few miles southwest of Villa Grove, in the 

 same state, on a hill of Carboniferous lime- 

 stone, perfectly polished pebbles are plentiful. 

 No lapidary could do more perfect work, but 

 facetting is not found. These are not gas- 

 troliths. 



A very interesting discovery of polished 

 pebbles was made by Mr. Philip Argall, of 

 Denver, in the Santa Eulalia mining district. 

 Chihuahua, Mexico. In one of the mines on 

 Santa Eulalia Mountain, the shaft penetrating 

 the massive Cretaceous limestone cuts a fissure 

 leading to a chimney lined with low-grade ore. 

 At the bottom of the chimney, at a depth of 

 1,200 feet below the surface, there is an ellip- 

 tical cave-like opening thirty by fifteen feet. 

 The bottom of the cave was plentifully strewn 

 with perfectly polished flint pebbles which 

 were cemented to the ealcite-covered floor like 

 plums. In other places the pebbles were found 

 in pot-holes in the underground water courses. 

 The history of these pebbles is believed to be 

 as follows: The deposition of ores was fol- 

 lowed by a period of solution during which 

 the caves were formed, and the limestone in 

 places rendered open and sponge-like by solu- 

 tion. The walls and floors of some of the 

 openings were covered with calcite, deposited 

 laigely from standing water. Where calcite 

 was not deposited, the solution of the lime- 

 stone has left nodules of flint standing out 

 from the walls of the caves. Similar nodules 

 loosened from the limestone by solution and 

 otherwise, have furnished the material for the 

 polished pebbles of the caves and water- 



