...axes in the direction of the bed of the rock, that is, of the movement of the lava when liquefied ; the finer grain often exhibited towards the tail or extremity of a current than at its source, the brecciated lavas which appear to have enveloped fragments in great number of the same material...

...aspect of the felspar crystals of many trachytes ; the broken and dislocated appearance of the leucitcs, felspars, and other crystals in many basalts ; the...material without any fusion even of their finest angles, &c. Of course, in these remarks I am referring solely to those lavas which after cooling exhibit a...

...into them ; the absence of a vitreous texture, even in their superficial portions, or in the scoriae, torn seething hot from the surface of the liquid matter...remarks I am referring solely to those lavas which after cooling exhibit a crystalline texture ; not to the vitreous lavas, such as the obsidian and pumice...

...axes in the direction of the bed of the rock, that is, of the movement of the lava when liquefied ; the finer grain often exhibited towards the tail or extremity of a current than at its source, the brecciated lavas which appear to have enveloped fragments in great number of the same material...

...axes in the direction of the bed of the rock, that is, of the movement of the lava when liquefied ; the finer grain often exhibited towards the tail or extremity of a current than at its source, the brecciated lavas which appear to have enveloped fragments in great number of the same material...

...axes in the direction of the bed of the rock, that is, of the movement of the lava when liquefied ; the finer grain often exhibited towards the tail or extremity of a current than at its source, the brecciated lavas which appear to have enveloped fragments in great number of the same material...