This time the descent commenced by the new gallery. Hans walked first as was his custom.  
We had not gone a hundred yards when the Professor, moving his lantern along the walls, cried:
 
"Here are primitive rocks. Now we are in the right way. Forward!"
 
When in its early stages the earth was slowly cooling, its contraction gave rise in its crust to disruptions, distortions, fissures, and chasms. The passage through which we were moving was such a fissure, through which at one time granite poured out in a molten state. Its thousands of windings formed an inextricable labyrinth through the primeval mass.
 
As fast as we descended, the succession of beds forming the primitive foundation came out with increasing distinctness. Geologists consider this primitive matter to be the base of the mineral crust of the earth, and have ascertained it to be composed of three different formations, schist, gneiss, and mica schist, resting upon that unchangeable foundation, the granite.
 
Never had mineralogists found themselves in so marvellous a situation to study nature in situ. What the boring machine, an insensible, inert instrument, was unable to bring to the surface of the inner structure of the globe, we were able to peruse with our own eyes and handle with our own hands.
 
Through the beds of schist, coloured with delicate shades of green, ran in winding course threads of copper and manganese, with traces of platinum and gold. I thought, what riches are here buried at an unapproachable depth in the earth, hidden for ever from the covetous eyes of the human race! These treasures have been buried at such a profound depth by the convulsions of primeval times that they run no chance of ever being molested by the pickaxe or the spade.
 
To the schists succeeded gneiss, partially stratified, remarkable for the parallelism and regularity of its lamina, then mica schists, laid in large plates or flakes, revealing their lamellated structure by the sparkle of the white shining mica.
 
The light from our apparatus, reflected from the small facets of quartz, shot sparkling rays at every angle, and I seemed to be moving through a diamond, within which the quickly darting rays broke across each other in a thousand flashing coruscations.
 
About six o'clock this brilliant fete of illuminations underwent a sensible abatement of splendour, then almost ceased. The walls assumed a crystallised though sombre appearance; mica was more closely mingled with the feldspar and quartz to form the proper rocky foundations of the earth, which bears without distortion or crushing the weight of the four terrestrial systems. We were immured within prison walls of granite.
 
It was eight in ............