258 COSMOS. 



been found to terminate in slender threads. Examples o1 

 these narrow openings may be found in three places in Ger- 

 many, in the " P faster -haute" at Marksuhl, eight miles from 

 Eisenach ; in the blue " Kuppe" near Eschwege, on the banks 

 of the Werra, and in the Druidical stone on the Hollert road, 

 (Siegen,) where the basalt has broken through the variegated 

 sandstone, and greywacke slate, and has spread itself into 

 cup-like fungoid enlargements, which are either grouped 

 together, like rows of columns, or are sometimes stratified 

 in thin laminae. The case is otherwise with gran it/3, syenite, 

 quartzose porphyry, serpentine, and the whole series of un- 

 stratified compact rocks, to which, from a predilection for a 

 mythological nomenclature, the term plutonic has been applied 

 These, with the exception of occasional veins, were probably 

 not erupted in a state of fusion, but merely in a softened con- 

 dition, not from narrow fissures, but from long and widely 

 extending gorges. They have been protruded, but have not 

 flowed forth, and are found, not in streams like lava, but in 

 extended masses.* Some groups of dolerite and trachyte 

 indicate a certain degree of basaltic fluidity ; others, which 

 have been expanded into vast craterless domes, appear to 

 have been only in a softened condition at the time of their 

 elevation. Other trachytes, like those of the Andes, in which 

 I have frequently perceived a striking analogy with the green- 

 stones and syenitic porphyries (which are argentiferous, and 

 without quartz), are deposited in the same manner as granite 

 and quartzose porphyry. 



* The description here given of the relations of position under which 

 granite occurs, expresses the general or leading character of the whole 

 formation. But its aspect at some places leads to the belief, that it 

 was occasionally more fluid at the period of its eruption. The de- 

 scription given by Rose, in his Reise nach dem Ural, bd. i. s. 599, of 

 part of the Narym chain near the frontiers of the Chinese territories, as 

 well as the evidence afforded by trachyte, as described by Dufrenoy and 

 Elie de Beaumont, in their Description geologique de la France, t. i. 

 p. 70. Having already spoken in the text of the narrow apertures 

 through which the basalts have sometimes been effused, I will here 

 notice the large fissures, which have acted as conducting passages for 

 melaphyres, which must not be confounded with basalts. See Murchi- 

 eon's interesting account (The Silurian System, p. 126) of a fissure 480 

 feet wide, through which melaphyre hae been ejected, at the coal-iaiua 

 at Corabrook, Hoar Edge. 



