Starting up the Rhine, we shall have passed out of Holland before we leave alluvial soil, and a route which has much more of geologic interest and variety, and is not devoid of beauty and historic association, is to go across the Belgian coal-fields, scenes of the worst European strikes, up the gorge of the Meuse. In passing, I note that the curious porphyroids of Bonney (14) and Renard have been recently blasted into in road-repairing, so that the next comers will have a better chance than for some years before, when the continuous attrition of geologists' hammers had rounded off every corner. At Charleville-Mezières, a typical provincial French town, we stand on the rim of the Paris basin, and gryphæas of the Lias abound. Thence, running along the rim of the basin past Sedan, we come to Luxemburg or Metz. Luxemburg is beautifully situated, being surrounded by canons cut into the sandstone here so typically developed that it is called the Luxemburg sandstone. If we go to Metz, the work of fortification still going on gives good sections in the Jura. Only beware lest you are charged upon by some too vigilant sentry, as a friend of mine was. I escaped by being careful not to have maps or note-books around in sight. However, if attacked, pick up a cidaris club and defend yourself manfully. We can go on to Treves, into the Eiffel, or down the Moselle, or to Saarbrücken, the great coal-center and first point attacked by Napoleon III, and down the Nahe to the Rhine. Whichever is omitted may also be taken as a side excursion from the Rhine.
Suppose, however, we go straight up the Rhine. We come first to Cologne. Climbing the cathedral, we see off on the southeast the seven blue summits of the Siebengebirge, whence the gray trachyte with sparkling sanidin crystals comes, that lines the winding staircase we have ascended. In the Siebengebirge is the cave of the dragon that Siegfried destroyed, and true it is, according to geologic tale, that once the volcano did cut off the mighty stream that glides in serpentine course beneath our feet. The victory was but for a time, however. Siegfried is dead, and so is the volcano, but dragons and rivers are hundred-headed and immortal, and the Nibelungen gold is still guarded securely. To the Siebengebirge, then, will be our next excursion, and we had best start from Bonn, the famous university town. We can there buy what guides we wish (16), and visit the collections of the Poppelsdorfer Schloss, valuable and beautiful themselves, and especially to us, as they illustrate by models and specimens what we are to see. Some of the rooms are fantastically decorated with bits of satin-spar and shells. Sturz's natural history store, one of the finest and largest—but not the cheapest—in the world, is in Bonn. His polyglot catalogue gives many hints for excursions to the collector.
