236 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [March 10, 



more than 1 inch in breadth near the middle of the body, and 2\- 

 inches in length without the head or tail, which are wanting) with 

 attached bodj-rings and other appendages bnt 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 iden- 

 tical colour of the altered Silurian formation in which they are 

 imbedded. There are but few places in the Silurian area of Wool- 

 hope 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 Down- 

 ton Sandstone ; but although the position of the Old Eed 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 inter- 

 vening 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 Sand- 

 stone, 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 imme- 

 diately 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 BeyricJiice, and a small coral, are asso- 

 ciated with the Eurypterus in the stratum referred to. At Ludlow the 

 section, when exposed, showed : — 1, the Old Eed Sandstone ; and, 2, 

 passage-beds, with OepTialaspis, Pterygotus, and Eurypterus. At 

 Ludford-lane adjacent, the following lower beds are seen : — 



1, Downton Sandstone. 



2. Shale containing Platyschisma helicifes &c. 

 v^ 3. Bone-bed, about 2 inches 



4. Stratum with fragments of Pterygotus &c. 



5. Upper Lndlow. 



No. 4 in this section appears to correspond most nearly with the 



