PLATE XLIX.
Remains of Encrinites.
Fig. 1. A polished slab of limestone formed of portions of the stems of encrinites; the white figures are produced by sections of the calcareous spar into which the ossicula are transmuted. The dark spots are the cavities of the entrochites, filled with mineral matter of a different colour.
Fig. 2, is the pentagonal base of the receptacle of the Derbyshire Encrinite.
Fig. 3. A mass of Derbyshire encrinal marble, with numerous portions of stems lying in relief.
The Derbyshire encrinal marble is so extensively employed in the manufacture of tables, chimney-pieces, vases, &c., that it must be familiar to every reader; and yet probably but few are aware of its origin, or of the nature of the fossil remains of which it is composed, and that give rise to the elegant figures in which its beauty consists. On Middleton Moor, near Matlock, extensive quarries of this marble are worked, and good specimens of the ossicula and stems may be easily obtained.[44]
[44] See Medals of Creation for "A Geological Excursion from Matlock to Middleton Moor, returning by Stonnis," p. 968.
Fig. 4. Part of the stem of a large Encrinite, (Cyathocrinus rugosus, of Miller,) from the Wenlock limestone, Dudley.
Fig. 5. A fine specimen of the lower part of the stem, and the root-like processes of attachment of the base, of the same species as fig. 4: from Dudley.
Fig. 6, is called the "Screw or Pulley-stone" of Derbyshire. These curious fossils are found in the chert (a kind of flint) which occurs in veins and layers in some of the limestone strata: they are siliceous casts of the interior cavities of the stems, and small branches of ossicula, of Encrinites. Plate XL VII. fig. 10, is a detached specimen of this kind.