Page:Quarterly Journal of the Geological Society of London, vol. 32.djvu/295

Rh OF &EJSTTC BEDS IN LEICESTERSHIRE. 215

decomposed ; and these are overlain by a thin irregular band of hard reddish sandstone from | an inch to 1 inch thick, whose surface is covered with casts of Axinus (formerly called Pullastra).

Then come about 2 feet of finely laminated black shales (No. 6). It was this bed which, in February 1874, yielded me the first fossil evidence {Cardium rhceticum and Avicula contorta) by which I was enabled to prove these beds to be of Rhaetic age.

From the next stratum (No. 7) in March 1874, 1 got a Starfish, the first found in British Rhaetics. Curiously enough, the same species occurred, about that time, to Professor F. Romer in the Rhaetic beds of Hildesheim *, whilst it has since been found by Mr. G. Embrey at Westbury- on- Severn. It has been determined by Dr. Wright to be his OpMolepis Damesii. I have recently found a thin band in the shales almost made up of the remains of these beautiful Starfishes, their joints occurring by thousands. There are apparently at least two distinct species.

This bed (No. 7) consists of rather dark shales with sandy partings. Here I also found a new species of Pholidophorus, which I propose, provisionally, to name P. Mottiana, after my friend Mr. F. T. Mott, President of the Leicester Literary and Philosophical Society. Avicula contorta and Cardium rhceticum also occur. There are, too, some curious oval markings, with fine stria? radiating from the centre ; but these may be inorganic. Worm-tracks are numerous. A white amorphous mineral, Kaolinite, with a little bitumen, fills many fissures • in these beds of shale ; and the cavities left by radiating selenite crystals cover the surfaces in great abundance. Flakes of mica spangle many of the sandy partings which occur in the upper part.

The uppermost shales seen in the section (No. 8) are very light in colour, and about 4 feet thick. All the shells already men- tioned occur in them, together with Modiola minima.

Indications of a bed of hard rubbly limestone are to be seen capping the brick-pit sections. Drainage-operations higher up the crest of the Spinney Hills, in connexion with new streets to be built there, have, however, lately offered a good opportunity of examining beds somewhat higher in the series than those already noticed.

The bed of limestone (No. 9) is nodular, the nodules occurring at intervals of a foot or more. They are intensely hard, but soon break up into cubical masses on exposure to the air, being traversed in all directions by cracks filled with calcite. I have recognized this limestone as entering inio the composition of Roman pavements found in Leicester; it would, in fact, present ready-made tesserae to the hand of the artisan. It has a conchoidal fracture, and is of a bluish tint, but grey on the outside. Fossils are very rare in it ; but I have found casts of Estheria minuta and Avicula contorta on the outer surfaces.

A second nodular bed of limestone exists, I believe, about 2 feet above the one just mentioned, and then beds of light- coloured clay and sand ; but here the drift obscures the section, and, as it thickens
 * Zeitschr. d. deutsch. geol. Ges. 1874.