. 1822.) Mr. Weaver’s Geological Remarks. 87 
lites and discites; while a little further south, Freiesleben was 
assured, after he had left the country, that the sandstone con- 
tains also beds of oolitic limestone, where it underlies the 
Wettin coal field; for the truth of this, however, the author does 
not actually vouch. 
c. Porphyry and Amygdaloid.—Porphyry occurs in_ great 
lying masses, of an indeterminate form, in the old red sandstone, 
on the SE. bank of the Wipper between Hettstadt and Burgor- 
ner, its immediate cover being coarse sandstone conglomerate. 
It is traversed by innumerable small veins of calcareous spar. 
Not far from hence porphyry becomes again visible near 
Meisberg, forming cliffs, protruding 56 to 70 feet high from 
amidst the old red sandstone. It is partly amygdaloidal, and 
reposes immediately on coarse siliceous conglomerate. 
It re-appears in a similar manner between Hettstadt and Gerb- 
stadt ; and porphyry has also been traversed under the same 
circumstances by the adit level of the mine Johann Friedrich. 
The old red sandstone, when adjacent to porphyry, acquires 
not unfrequently a porphyritic aspect. 
d. Coal Fields. Ades ; 
1. The North Western (vol. iv. p.227—237).—On this Freies- 
leben remarks, “ [tis quite certain that the coal which occurs 
near Opperode, in the Principality of Anhait-Bernburg, lies in 
the rothe todtliegende.” In proceeding from the vicinity of 
Opperode on the N. toward the transition tract on the S., the 
beds succeed each other in the following descending order: 
1. Brownish-red, ironshot, fine-grained, rothe todtliegende, 
‘with occasional larger grains of quartz, clay slate, and flinty 
slate ; regularly stratified, strata 1 to 14 inch thick, dipping 15° 
to the NW. and affording excellent building stone, 7 fathoms to 
9 fathoms 2 feet thick. 
2. Conglomerate, of unequal grain, iron-shot, some of the peb- 
bles of quartz and slate being 8 and 9 inches in diameter; 32 
inches thick. 
3. Sandstone, same as No. 1, alternating with thin layers of 
reddish-grey marly rock ; 35 fathoms thick. 
4. Slate clay, bluish-grey, and sandy, with numerous impres- 
sions of vegetables; 5tathoms 5 feet thick. 
5. Roof shale, bituminous ; 1 to 2 feet. 
6. Coal; 2 feet. 
7. Floor shale, resembling that of the roof; 31 feet. 
8. Conglomerate, very coarse grained ; 4 fathoms 4 feet. 
9. A second seam of coa/, but not worth working. 
10. Blue rock, resembling No. 4. 
11. Conglomerate, coarse-grained, being the lowest of the 
series. 
The upper coal seam dips pretty rapidly near the surface, but 
in descending, it maintains a general inclination of 15° to 20°, 
