and Volcanic Substances. 235 
count of the part of France he describes from Auvergne, 
through Velai, Viverais, &c. to the mouths of the Rhone, 
furnishes replique sans reponse. 
(e) The summit-basalt of the Saxon and Bohemian 
range, from Elba to the North, and Franconia to the South, 
consists of round hills and nodules of granite and other primi- 
tive rocks of that formation on the back of which, and on 
the highest points, we find basalt in the form of Cones, 
Domes, Plains, &c. These basaltic summits are insulated ; 
they do not consist of more than ;',%; of the extended chain 
on which they are dispersed with considerable uniformity ; 
they are covered often with greenstone ; they cover gravel, 
coal, and sandstone. They are prismatic ina great degree, 
and very solid and regular, as Stolpen, about eighteen miles 
east of Dresden. Spitzberg, the highest point of the chain, 
three thousand eight hundred feet above the sea, is full of 
metallic veins, but the basalt surmounting it, contains none. 
Meisner in Hesse, is covered by a table of basalt three 
hundred seventeen feet thick. The body of the mountain 
is red sandstone and limestone covered by bituminous red . 
marle, on which rests the basaltic mass. In this chain 
none of the valleys are filled with basalt, as they would 
have been, if this rock had been thrown out as a Lava. 
Reply. These are probably boulders: the ground has 
been carried away by the long and repeated action of cur- 
rents. 
Those who have considered the boulders of the Iura, and 
attended to Mr. McCulloch’s suggestions of the sameness 
between the granite strata of the Scotch isles, and the cor- 
respondent boulders of the main land, will not allow this 
to be an objection of great weight. _ 
Moreover, exactly the same objection applies to its sup- 
posed aqueous formation, was the basalt congregated in the 
small compass of the top of Meisner when it fell there‘ 
Who can believe this ? 
-. Dr. Richardson’s objections are considered at length by 
Breislak, ch. 113 and seq. but Richardson has certainly 
ranked petrosilex and hornstone among the basalts by mis- 
take. 
I have often had occasion to recur to the old acknowl- 
rac rule of reasoning, we can argue only from what we 
now. 
