149 



The length of the accessible section is considerable, but it is cut off at 

 either end by several faults. So it is best to confine ourselves to the low bank 

 ■and river section which extends from the first beds visible west of the foot- 

 bridge, to the cliff of green and giay shales, now rather well known and well 

 hammered by the Ludlow geologists. Only the north bank shows the section. 

 The beds, though they doubtless cross the river in some places, are mostly lost 

 on the south side by the considerable fault which runs along the course of the 

 river in a direction about "W. by N."W., and not quite in the same direction as 

 the river. Such dislocations in many places cross the Caradoo range on its 

 S. end. 



Measured roughly along the bank by paces, the Trinucleus shales, with 

 the calcareous gray layers at their base, occupy 130 yards, dipping at a low 

 angle. For 40 yards they form only shelves in the river bed, and are slightly 

 nodular and calcareous at the western end.* Then, for 45 yards, the low cliff 

 exhibits green and gray concretionary shales of a very uniform fine grain, with- 

 out bands of limestone or sandstone of any kind, and full of various forms of 

 Trilobites, chiefly Trinucleus concentricus, easily known by the laced border. 

 Ampyx, Bemopleurides, Liduis, and Calymene, are more rarely found. But a 

 tolerably full list may be found in the paper above referred to in the Quarterly 

 Geological Journal for 1854 — [Aveline and Salter). 



The angle of dip in these shales is seldom more than 25°, except where 

 they are overlaid by the May Hill Sandstone bands, where the dip accidentally 

 deepens to about 30° or even 35° in parts, with which dip the beds plunge into 

 the trout pool. The exact spot is now easily marked ; a couple of large trees 

 have fallen — one on each side of the deeper water (it is but a few feet in sum- 

 mer time), and a hoUy tree hanging from the bank, exactly covers the line 

 of unconformable junction. Koughly measured, the thickness of the gray (or, 

 when weathered, greenish) Caradoc shale is 35 feet, and in all this, no beds of 

 limestone or calcareous sandstone occur. 



This is immediately followed by bands of impure Limestone. 3 or 4 inches 

 or less in thickness, with greenish or grey friable shales between the limestone 

 bands. The shales so exactly resemble the underlying Caradoc shale, that any 

 one might mistake the one for the other. But when hammered, they yield not 

 a single Trinucleus, or any of the characteristic fossils of the Caradoc shale. 

 On the contrary, they contain Pentamerus Unr/uifer in abundance, a fossil which 

 abounds aU along the line of junction — in these May Hill rocks up to Buildwas 

 and the "Wrekin base. In the beds of limestone are Pentamerus, Atrypa reticu- 

 laris in plenty, Leptcena, transversalis, L. scissa, and Chonetet Icevigata, some 

 corals (Petraia and Favosites) ; and these abound, and are wholly unmixed 

 with any of the small Nucula, Bellerophon, Holopea, &c,, which are found 

 in the lower (Caradoc) beds. 



* Similar beds, with rather thicker bands, occur along the course of the river for 

 some way up. The ground must be much faulted judging from the area covered by 

 these beds. The same grey shale extends to Church Preen. 



