more than 1 inch in breadth near the middle of the body, and 2-1/4 inches in length without the head or tail, which are wanting) with attached body-rings and other appendages but having neither head nor tail, single body- rings of large size, detached heads, thoracic segments, tails of Eurypterus megalops, swimming-feet, claws, &c. Many might have been obtained entire, if the thin stratum in which they occur could have been worked ; but from its position it was impossible to procure anything but detached fragments (though every piece of shale was crowded with them), so that the Crustacea were invariably broken, and I fractured many entire specimens in consequence. They are of a uniform brown colour, while those from Lesmahago, in Scotland, are always black, and are of the identical colour of the altered Silurian formation in which they are imbedded. There are but few places in the Silurian area of Woolhope where the so-called passage-beds, or the intermediate strata between them and the Old Red Sandstone are exposed ; but some parts of this series may be seen in an old quarry at Purton, near Stoke Edith. At one end of the quarry there is a fine-grained, moderately hard, yellow sandstone, which may represent the Downton Sandstone ; but although the position of the Old Red Sandstone can easily be detected by the colour of the soil in the lower ground between that spot and the railway-station, and towards Hagley Dome, neither the exact thickness, nor the character of the intervening bands can be accurately determined. A mason informed me that this yellow sandstone was an excellent building- stone, and of considerable thickness ; if this represents the true Downton Sandstone, then the rich crustacean-bed may belong to the bone-bed series, as the upper Ludlow shales underlie it ; for, supposing the overlying sandstone to be the " Downton rock," it would determine the true position of the crustacean zone. This sandstone is immediately underlain by a coarse sandy bed full of remains of plants, including seed-vessels of Lycopodiaceae, and fragments of Eurypterus and Pterygotus. This is succeeded, in descending order, by a thin stratum of sandstone, below which is the thin band of pale green, micaceous, sandy marl, only a few inches thick, so rich in Crustacea, which is again underlain by another thin layer of sandstone, below the whole of which the Upper Ludlow formation, with the usual fossils, appears rising at a considerable angle ; and the entire section indicates considerable disturbance. A few small well-preserved seed-vessels, univalves, and Beyrichioe, and a small coral, are associated with the Eurypterus in the stratum referred to. At Ludlow the section, when exposed, showed : — 1, the Old Red Sandstone ; and, 2, passage-beds, with Cephalaspis, Pterygotus, and Eurypterus. At Ludford-lane adjacent, the following lower beds are seen : —
1, Downton Sandstone. 2. Shale containing Platyschisma helicites &c. 3. Bone-bed, about 2 inches 4. Stratum with fragments of Pterygotus &c. 5. Upper Ludlow.
No. 4 in this section appears to correspond most nearly with the
