1868.] 



HOLL — SOUTH DEVON AND EAST CORNWALL. 



417 





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Houses, fossils are specifically far 

 less numerous than they are at 

 Landlake, the only additions to the 

 already known species from this 

 locality being Tentaculites annu- 

 latus, Schloth., and a small unde- 

 scribed species of Serpula ; but the 

 limestone at Little Petherwin, al- 

 though in the same mineral con- 

 dition, contains few or no fossils. 

 Underlying these calcareous beds 

 are two small patches of volcanic 

 rock, the one a little north of South 

 Pethermn, the other at Bolathan, 

 a mile to the west of the former ; 

 and it is perhaps worth noting that 

 these igneous rocks hold pretty 

 much the same relative position to 

 the Petherwin limestones that the 

 larger band of Lewannick does to 

 the limestone of Trewen, and may 

 possibly be offstanding patches on 

 the same horizon. Possiliferous 

 slates containing/S/9^/•^/€ra disjuncta, 

 Cyathocrinus ellipticus, and an 

 Orthis occur in the lane leading 

 fromTrekellearn Bridge to PoUinny, 

 about halfway up the hill ; and 

 the similar olive and speckled slates 

 with ferruginous seams, which oc- 

 cupy the depressed country round 

 about Trewarlet, and beneath which 

 the pale-green slates of Brocka and 

 Trevoza are seen to dip, are again 

 fossiliferous at Larrick, Trewarlet, 

 and the south of Laudue ; and on 

 the banks of the Inny below Round 

 Bury, troughed among the beds 

 which overlie the volcanic rocks on 

 either side of the river at Trecarrel 

 Bridge, a small patch of highly cal- 

 careous ash occurs, which appears 

 to be sufficiently on the same ho- 

 rizon as the limestones and calca- 

 reous seams of south Petherwin and 

 Trewarlet, to be regarded as belong- 

 ing to the same group. 



It would appear, therefore, that 

 the place of the limestones and cal- 

 careous seams of South Petherwin, 

 2g2 



