1893. NOTES AND COMMENTS. 13 



between the frog orchis [Hahenavia vividis) and the spotted orchis 

 {Oychis 7nacnlata). It was found at Longwitton, in Northumberland, 

 and shows, in a marked manner, a blending of characters derived 

 from its two very distinct parents. The spur, for instance, is neither 

 long nor short, but intermediate between the forms characterising 

 the Hahenaria and Orchis respectively. The hybrid receives the some- 

 what formidable name of Habenari-orchis vmdi-maculata. 



Attention has been directed to the subject of Lunar Volcanoes 

 by Mr. J. B. Hannay [Nature, vol. xlvii., p. 7). He thinks that many 

 of the craters look more like some disturbance in a semi-liquid sur- 

 face than an accumulation of volcanic debris ; and remarks that the 

 rise and fall of a fused slag through holes in its solidifying crust, 

 form features exactly like the craters in the moon. He suggests 

 that, in the case of the moon, the rise and fall would be caused by the 

 tidal motion of its still liquid interior. Mr. S. E. Peal also enquires 

 {Geological Magazine, Nov., 1892, p. 501) whether the moon "could 

 retain from the igneous-molten era, to its present intensely cold, airless 

 and waterless condition its pristine surfacing, the very poles them- 

 selves being covered (it is urged) with large and small volcanoes, 

 untouched by the hand of time." He has, however, written a book, 

 which he speaks of as " my Theor}' of Lunar Surfacing by 

 Glaciation." 



The supply of natural gas and petroleum in Canada does not yet 

 approach in importance that of the United States ; we are glad to 

 see, however, by the recently-issued First Report of the Bureau of 

 Mines, 1891 [Ontario] , that the industry is making steady progress. 

 An Act has wisely been passed to prohibit the wanton waste of the 

 by no means inexhaustible supply, and to provide for the compulsory 

 plugging of unused bore-holes. The same report shows that nickel 

 mining, of which so much was expected, progresses but slowly, the 

 new alloys of nickel-steel not having yet come into use to any great 

 extent. The ore is a mixture of copper-pyrites and nickeliferous 

 pyrrhotite, usually associated with greenstone. 



An interesting discovery of Lithographic Stone is recorded in 

 the seventh volume of the Mineral Resources of the United States, lately 

 issued by the U.S. Geological Survey. Material of excellent 

 quality, comparing very favourably with Bavarian stone, has been 

 found near Little Rock, Arkansas ; and stone that has been tested 

 and found serviceable, occurs at Fincastle, Virginia, and also in 

 Blanco County, Texas. Preparations have been made for working 

 the stone at the three localities. In England, trials for Lithographic 



