Cranmer Quadrant, where it is seen bringing down the lower beds of the Upper Keuper alongside the markstones of the Lower Keuper. This fault strikes north 40° west, with a throw of apparently about 15ft; it is not again seen. It so mush resembles. No. 1 fault, as seen on Blue Bell Hill, that one can scarcely wonder that, in the absence of more complete data, the Survey should have regarded it as a continuation of the same fault. Reverting to No. 1 fault, it evidently forms quite a focus of small dislocations on Blue Bell Hill, varying in direction between west and north. One of these, bearing 10° north of west, and throwing down the Lower Keuper against Bunter about 10ft., produces the triangular patch of Bunter, just at the apex of which were a few feet of Lower Keuper capping the Bunter. When these beds were cut through during the formation of Turner Street, a remarkably interesting section of the conglomerate at the base oi the Lower Keuper was exposed.[1] Unfortunately, however, it has since been removed for building purposes. Another fault, having a down throw of 6ft. 3in. on the east side, is traceable crossing Blue Bell Hill Road 12° west of north, and coming out in the cliff in Lower Bencon Street. The other minor dislocations marked on the new map, mostly parallel with this, all have a downthrow to the east, but they are of no further importance than to serve to show the general tendency of the down-throw of the faults on Blue Bell Hill, east of No. 1 fault. In fact I met with mere dislocations radiating from No. 1 fault than in any other part. I ought not to omit to mention that No. 1 fault is finely exposed in the section opposite the saw mills on the Blue Bell Hill Road. The Lower Keuper between Pease Hill Road and the Robin Hood's Chase is also much disturbed by faults. Two or three may be seen in the brick yard there, but others, having a downthrow to the north-east, probably exist; for, on the down-throw side of No. 1 fault at the junction of Cooper Street and Pease Hill Road, the Bunter was met with at a depth of 16 feet, while near the Chase, with a rise of ground of about (illegible text) feet, the Bunter was not reached till a depth of 54 feet of Lower Keuper had been passed through, and then only on the upthrow side of a fault which was found to cut through the well. Again, just where we might expect to find the lowest beds of the Keuper, namely, at the bottom of Dame Agnes Street, over 40 feet of water-stones have been pierced without reaching the Bunter. This, coupled with the fact that brickyards existed years age along the bottom of Blue Bell Hill on St. Ann's Road, leads me to infer the existence of a series of transverse faults running nearly parallel with that road, and letting in the higher beds of the Keuper.
While tracing the fault I have mentioned in the Beacon Street Cliff, I came across some very interesting geodes in the Lower Keuper sandstone beds. The geodes ramified in the thick beds of sandstone without any regard to the lamination; were lined with rhombohedral crystals of calcite, occasionally tinged with copper and a black mineral—probably manganese: and appeared to have been formed long after deposition and consolidation of the rock. The crystals were all rhombohedrons, except where the copper or the black substance was present, when they became double six-sided pyramids. These are the first crystals of calcite, as far as I know, that have been found in the Keuper—at least in this district. The geodes extended through about three feet of the marlstone, and were confined literally to the space of a few square yards. The calcareous matter appeared to have come from above, a thin lenticular band of it, about three feet long, being met with about five feet above where the geodes were found.
To be continued.
- ↑ This conglomerate is described at a later stage.
