1893. NOTES AND COMMENTS. 13 
between the frog orchis (Habenaria viridis) and the spotted orchis 
(Orchis maculata). 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 Habenaria and Orchis respectively. The hybrid receives the some- 
what formidable name of Habenari-orchis viridi-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 débris ; 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 Theory of Lunar Surfacing by 
Glaciation.” 
Tue 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 
