WILMORE : THE STRUCTURE OF SOME CRAVEN LIMESTONES. 37 
of this anticlinal there is much calcite and iron oxide. The 
upper beds are mostly shales. Dip varies from 60"" to 70° S.E. 
Fossils are very numerous in the shales. Among them the 
following are common : — Syringopora reticulata, S. ramulosa, 
LitJwstrotion sp., Amplextts Coralloides, Zaphrentis cylindrica, 
Z. cornucopice, plates, spines — sometimes cups and heads crushed 
and broken — of echinodermata, e.g., Archoeocidaris ; Fenestella 
very plentiful ; Gasteropoda, very plentiful, e.g., Eulima sp. 
and Orthis Michelini ; Productus punctatus. 
Exposures on the northern side of the anticlinal. At Gill 
Rock, flaggy, well-bedded limestones have shales interbedded. 
There is in this quarry more shale than limestone. An over- 
thrust fault is seen, The fossils are the same as at Rain Hall 
and Thornton (Plate V., Fig. D). 
At Thornton Church, in the cutting in the roadway, there 
is a small exposure. Limestone of a muddy character gradates 
into calcareous shales. Dip, N.N.W. about 40°. Fossils are the 
usual stems and plates of echinoderms imbedded in a black 
ground mass. Prod, semireticularis and P. pustulosus are found 
(Plate IV., Fig. C). 
Three quarries at Broughton Fields show massive, well- 
bedded dark-blue limestone, with dark calcareous shale partings. 
The shales are seen to be studded with round and elliptical 
colonies of Syringopora. The growing point or growing circle 
may be seen usually on underlying limestone and the colony 
spreads out into a lenticular mass of from 6 inches to 2 feet or 
more in diameter. These coral masses are common and may 
frequently be got out fairly complete. The same corals occur 
in the solid limestone. 
The eastern quarry of the three shows some very interesting 
features. First there is the black, shaly limestone, with numer- 
ous fossils in calcite already mentioned. Secondly there is a 
curious overthrust fault with the under strata somewhat bent 
over, and in connection with this there are fine systems of anas- 
tomosing calcite veins. Where the crushing is most marked 
the calcite veins are most numerous, and at one place a fine 
rhombohedral crystal of calcite is seen in the middle of dark- 
grey limestone, showing development of crystalline structure 
