MiddleJurassic

29 CLAY over the UPPER OOLITE. ———————
As the bottom only of this Clay contains organized fossils, and most of these being Zoophites, attached to the rock by their roots, and apparently extended up into the Clay by their growth, they need not be considered as the products of a separate Stratum, but rather as the appendages to the top of the upper Oolite rock, which is thus covered with Clay. The organized fossils being all filed with stone, further confirms their relationship to the rock. Lying in Clay they are all loose, and easily collected and cleaned. The stony matter contained in the shells, which are entire, has few or no marks of ova; nor is there much of this general characteristic of the rock in the first four of five feet beneath the clay. Many of these fossils can be only be found in excavations which expose the top of the rock. Corals, tubipora, fig. 4, and fragment of millepora. fig. 5 may be collected from some of the ploughed fields south of Bath, which are on the plane of the upper Oolite rock. The tenacious and adhesive nature of this soil readily distinguishes it from that of the Stratum beneath, and accurately defines the boundary of the stone land.
——————— UPPER OOLITE, or Calcareous Freestone. ———————
SOIL.—	Colour, yellowish brown.
	Consistence, loose, crumbly, stony, with a large proportion of small stony fragments; over the Freestone some loose ova; over other parts of the rock some large flat stones, commonly called Stonebrash.
	State of moisture, absorbent: where sufficiently free from small stones may be kneaded.
SUBSOIL, small stone with a little soil, and fragments of the rubble stone which lies over the rock.
EXCAVATIONS, always dry.
STRATUM, masses of rock in beds, divided by large open vertical joints.
	Colour. The Freestone part yellowish white; other beds, some gray, and some almost blue in the middle. Freestone, calcareous, soft, oviform; cuts easily with a toothed saw or any edge tool; used in the repair of Westminster Abbey; alternates in the rock with other harder calcareous beds, but little interspersed with ova.
	Disintegration. See remark on the Portland rock, page 15, applicable to this.
WATER,	hard, transparent: springs copious and numerous, in roads, ditches, and brooks; white from hasty rains.
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This is the thickest of the calcareous rocks which form the great pile of Strata called the Stonebrash Hills. Where it occurs it forms the greatest breadth of their dry surface, and occasions many deep excavations for water. In these perforations, and in numerous deep quarries for the fine soft Freestone, which is imbedded between very thick beds of different sorts of stone, the nature and properties of the whole rock are ascertained. This most valuable part of it varies much even in quarries of the same neighbourhood, south of Bath. The other sorts of stone are rarely used but in rough walls around the fields, and in the stone [30] buildings common to its surface. The length of this Stratum, from unconformableness or other causes, is more deficient than either of the other rocks on the Stonebrash Hills. This might be adduced as one of the many instances of the necessity of attending to the course and full extent of every Stratum, before any geologist can decide upon the number contained in the British series; and hence also it must be evident, that those who have taken only partial views of the subject must be perpetually liable to error. Until the clay was removed from its top by the recent excavations of canals, &c, this rock was thought to contain but few fossils, and thus to be sufficiently distinguished from the under Oolite, which is most abundantly stored with them; and considering these fossils as appendages to the top of the Stratum, the remark still applies as to the rock itself. That extraordinary fossil zoophite, the pear encrinus, was first discovered most perfect with its root attached to the top of the rock, in a field belonging to my truly good friend, the Rev, Benjamin Richardson, at Berfield, near Bradford; and thence for some time afterward was called the Berfield fossil. Several species of zoophites, with five or six species of inequivalved Bivalves and Echini, are the most numerous identifications. Between the beds of stone deeper in the rock, oysters and a few inside casts of equivalved bivalves occur; very small univalves, similar to those in Forest Marble, are numerously blended with ova and minute corals, in some of the upper beds, which are very indifferent Freestone. On account of the scarcity of fossils in the rock, and the rare exposure of those on its top, and the great variation it is subject to, this seems the most difficult to trace to its extremities of any of the rocks which compose the Stonebrash Hills.
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ORGANIZED FOSSILS of the Clay over the Upper Oolite.
FIG.
1 Pear Encrinite 2 Vertebra ditto 3 Stems ditto 4 Tubipora 5 Millepora	Bradford, Berfield. Farley Castle, Hinton. Winsley, Pickwick. Broadfield Farm, Farley Castle. Broadfield Farm, Farley Castle, Hinton, Pickwick, Westwood.
6 Chama crassa 7 Plagiostoma 8 Avicula costata 9 Terebratula digona: the long variety	Stoford Bradford Bradford, Hinton, Winsley Farley Castle, Stoford, Bradford, Winsley, Pickwick.
10 Terebratula reticulata	Farley Castle, Bradford, Stoford, Hinton, Winsley, Pickwick.
ORGANIZED FOSSILS of the Upper Oolite Rock.
FIG.
1 Tubipora 2 Tubipora 3 Madrepora turbinata 4 Madrepora 5 Madrepora flexuosa	Broadfield Farm. Combe Down. Westwood. Combe Down. Farley Castle. Broadfield Farm. Broadfield Farm. Castle Combe.