PROCEEDINGS 



OF 



THE GEOLOGICAL SOCIETY OF LONDON. 



1832. No. 26. 



February 29. — A paper "On the Secondary Formations in the 

 neighbourhood of Ludlow," by J. R. Wright, Esq., employed on the 

 Ordnance Trigonometrical Survey, and communicated by Col. Colby, 

 F.G.S., F.R.S., &c, was first read. 



The district described in this memoir occupies a surface of about 

 1 67 square miles around Ludlow, and consists of clay-slate, transition 

 limestone, with accompanying beds of shale, old red sandstone, car- 

 boniferous limestone, the coal measures, and basalt. 



The clay-slate is not described in detail, as it did not form part of 

 the author's personal investigations. The transition limestone and 

 shale are staled to occupy about one-third of the district. The lime- 

 stone occurs principally in the lower part of the formation, not in 

 regular strata, but in nodules intimately united to the shale in which 

 they are imbedded. The upper part of the formation consists chiefly 

 of a dark bluish grey rock, which passes into a soft argillaceous shale, 

 and contains occasionally calcareous concretions. The thickness of 

 the deposit is estimated to be between 800 and 1000 feet ; and the 

 dip of the strata is stated to vary from 8° to 22°. Besides the con- 

 tinuous band which ranges to the westward of Ludlow, the transition 

 limestone constitutes the narrow ridge, rising above the old red sand- 

 stone, called Tinker's Hill and Caynham Camp, about two miles to 

 the south-east of that town. 



The old red sandstone, the next formation described, is stated to 

 occupy about one half of the district under consideration, and to be 

 composed of soft, micaceous sandstone, conglomerates, and beds of 

 limestone or cornstone. The general dip of the strata is said to be 

 about 8° to the south-east, and the thickness of the formation is es- 

 timated to be from 400 to 700 feet. 



The carboniferous limestone is mentioned as occurring at only two 

 places, Knowl Hill and Oreton, the most southern and northern 

 points of the Titterstone-Clee-Hill range. The thickness of the 

 principal stratum is said to be twelve yards, and the dip of the for- 

 mation to vary from 20° to 75°. 



The coal measures are shown to be confined to the same range, 

 and to consist of millstone grit, surmounted by several seams of coal, 

 alternating with the usual strata of shale and sandstone. Sectional 

 lists are given of the principal workings, and the great seam is said 

 to be from 3 to 10 feet thick. The coal-field is much disturbed by 

 faults, and the measures have been partially acted upon by the ba- 



