Some New Features in the Geology of East Nottingham.[1]
By J. SHIPMAN, Esq.
Any one who has seen the Government Geological Survey map of the Nottingham district (71 N.E.) will hardly fail to have noticed two white lines stretching across the north-east of Nottingham. Those white lines mark the course, or what the Government surveyors believed to be the course, of two important faults, or dislocations of the rocks. The white line nearest to Nottingham takes a straight course from Colwick Wood, in the south, to Patchitt's Park, in the north. The other white line describes a parabolic curve, starting from the top of Sneinton Dale, sweeping round by the Hunger Hills and disappearing about midway between Carrington and Sherwood. To the geologist faults are peculiarly interesting, and they sometimes account for a good deal of what is observed in the physical features of a district. They are the unwritten records of the motion, at some remote period in the past, of those natural agencies which we know are ever at work somewhere at great depths, producing oscillations of level in the earth's surface, But, apart from whatever may be the origin of faults, there are some physical features connected with the curved white line which, to say the least, have always been perplexing to those who have cared to pay much attention to local geology. There has hitherto been an air of mystery about it, and nobody was ever able to meet with if at any part of its course. Even Professor Hull speaks disappointedly, in his work on the "Triassic Rocks of the Midlands," at not being able to find the fault just where it was marked to cross Woodborough Road at the end of Red Lane. This fault has hitherto been an object of interest chiefly because if was abnormal for a fault receding at both ends from the fault forming the opposite side of the trough, to help to produce a downthrow of the rocks lying between. It will readily be understand, therefore, why the course this fault really took should be an object of solicitude for years to local geologists. Indeed, I very well remember learning some of my earliest lessons in field geology while trying to trace it; and it was while engaged in the same work in the early part of this year, on account of the unusual facilities afforded by excavations all ever that part of Nottingham, that I discovered such serious discrepancies in the Geological Survey's mapping as induced me to resurvey the north-east part of what formed the old borough—that is, the area lying between Mansfield Road, Great Alfred Street, and Coppice New Road, and the result is the map which I now bring before you. In compiling this map, I have necessarily had to fall back, to some extent, on my recollection of what was the geological character of some parts now built upon, and I have found these observations, begun in 1868, very useful in elucidating what would otherwise have been almost beyond reach. The task was far from being an easy one, however pleasant field geology may be. Even where the character of the strata was exposed by sections I found the Keuper, which forms the lower pert of the area, extremely difficult to deal with, both in the tracing of faults and in determining the boundary line between the Upper and Lower Keuper. Many spots, too—geologically hallowed ground, ground unusually prolific in interesting points—had to be
- ↑ Read before the Nottingham Naturalists' Society, Nov. 28th, 1877. The paper was illustrated with a geological map, sections, photographed sketches of the main faults, the site of the geodes, and of the conglomerate.
