7. Transition trap. The trap rocks, which are stone, and amygdaloid, alternate in beds with greywackc and greywacke slate.
8. Transition porphyry. The transition porphyries have a basis either of clay-stone, felspar, or horn-stone, and occur in beds in greywacke, or in masses resting upon it.
C. Raiz Rocks.
Flcetz rocks surround the Hartz on every side, and are spread from thence over the hilly parts of Lower Saxony. The following are the flcetz rocks met with in the Hartz : Old red sand-stone, clay porphyry, alpine lime-stone, older gypsum, variegated sand-stone, newer gypsum, and third flcetz sand-stone.
1. Old red sand-stone, or the first ficetz sand-stone. This well known rock, the dunstone of English mineralogists, occurs in considerable abundance, and in this country contains beds of coal.
2. Clay-stone porphyry. This rock occurs in beds which alternate with the red sand-stone. The beds vary in thickness from a few inches to many fathoms. It passes into the bounding sandstone, a fact illustrative of the cotemporaneous formation of the two rocks.* 3. Alpine lime-stone, or first ficetz lime-stone. This lime stone occurs in considerable abundance, and generally rests on the red sand-stone.
4. Older gypsum, or first ficetz gypsum formation. This formation, which is principally composed of foliated granular gypsum, and compact gypsum, also contains selenite, rounded cotemporaneous portions of radiated gypsum, stinkstone, and sometimes fibrous gypsum. It
rests on the preceding formation.
5. Variegated, or second fixtz sand-stone. This formation•, which is probably identical with the red ground of Eng lish mineralogists, rests upon the older gypsum.
6. Newer gypsum, or second ficetz gypsum formation. The principal rocks in this formation are foliated granular, fibrous, and radiated gypsum. It rests on the variegat ed sand-stone, and sometimes even alternates with it.
7. Third fieetz sand-stone. This sandstone has generally a grey or white colour, and contains subordinate beds of slate clay, indurated marl, and coal. It appears to rest upon the newer gypsum and the variegated sandstone.
D. Alluvial Rocks.
The rocks of this class are calc-tuff, loam, clay, brown coal, bog iron ore, peat, and rolled masses, of different kinds.
The following works may be consulted, as affording ac curate and extensive details in regard to the natural history of the Hartz.
1. Erfahrungen von innern der gcbirge nach beobachtun gen gesamnzlet and herausgegcben von F. NV. II. von Tre bra. Fol. 1785.
2. Beobachtungen fiber den Harzgebirge nebst einem Pro flrisse als ein Beitrag zap mineralogischen naturkunde von G. S. 0. Lazius. 2 vols. Hanover, 1789 3. Bemerkungen iiber den Harz von J. C. Friesleben, 2 viols. Leipzic, 1795.
4. Hausmanns Norddeutsche Bcitrdge. 1806.
5. De la richesse minerale, par A. M. Heron de Villefosse. 4to. 1816.
See the article BROOKER.