230 ME. L. D. STAMP ON THE HIGHEST [vol. lxxiv, 



there is recorded as Chonetes striatella var., an interesting form the 

 valves of which are more convex and elongated than in the normal 

 type, and a pustulated ornamentation may almost obliterate the 

 radial striations. The pustules probably mark the point of attach- 

 ment of spines, and thus the form may be analogous to the well- 

 known spinous modifications of such genera as Productus and 

 Acanthothyris. This variety of Chonetes has been noticed in 

 typical Rhynchonella Beds, below the horizons in which the t} T pe 

 form, Ch. striatella, appears, and it ranges through the Lower 

 Chonetes Beds but has not been seen in the Upper Chonetes Beds. 



(b) The Upper Chonetes Beds present a lithological change from 

 the lower group, which is more or less marked in different sections. 

 The strata of this division are for the greater part well-bedded 

 slightly-arenaceous flagstones, which are more resistant to weathering 

 than the lower beds : consequently they form the ' capping ' of many 

 hills, and control the gentle dip-slopes. On the more barren hills, 

 such as Caer Caradoc and Hoclrey Hill, large slabs of these rocks 

 may be seen. They are 2 or 3 inches thick, but often many 

 feet in length and breadth. The surface of these masses undulates 

 gently, and this ma}*- be due to tidal or wave action, but is certainly 

 not ' ripple -marking ' in the ordinary sense of the term, as the 

 rounded crests of the gentle undulations are at least a foot apart. 

 On the surface of these slabs most of the fossils characteristic of 

 the Lower Chonetes Beds may be seen; but the fossils, whether 

 isolated or grouped together, are confined to the division -planes, and 

 are not distributed through the mass of the rock. When freshly 

 broken the flags are blue-grey, but they weather to a 3 T ellow-brown. 

 These hard flagstone -bands have been much in demand locally 

 for building purposes. 



The sediments overlying the flags generally show a return to a 

 type of lithology very similar to that of the Lower Chonetes Beds. 

 They differ in retaining, however, a certain amount of lamination 

 which is typically absent in the lower beds. They have, moreover, 

 a greenish tint approaching in appearance the colour of the 

 Temeside Shales. 



These Upper Chonetes Beds correspond approximately to the 

 ' Sjpirifera-elevata Shales ' of the Ludlow area. The latter fossil 

 is, however, neither very common nor widely distributed in the 

 disti'ict examined. Yet, at certain localities (as, for example, 

 south-east of Five Turnings) there occur thin bands crowded with 

 fossils, among which Spirifera elevata, Chonetes striatella, and 

 Orthis lunata are particularly abundant. Although these bands 

 are certainly not ' bone-beds,' they doubtless result from causes 

 similar to those favouring the formation of 'bone-beds' : namely, the 

 initiation of unfavourable conditions killing off large numbers of 

 organisms of all kinds ; rather than the temporary existence of 

 favourable conditions causing a rapid multiplication of individuals. 

 The significance of fossil-bands of small individuals was emphasized 



