124 REPORT — 1861. 



caverns. The base of the breccia is on the same level as the bone-bed in the Wind- 

 mill Hill Cavern ; and there can be no doubt it filled, either wholly or partly, a 

 north and south fissure. Nearly the whole of the dyke was revealed during the'old 

 quaiTying operations. In the exposed face there were visible several 'fine bones ; 

 but even a remarkably fine left ramus of a lower j aw bristling with, teeth, of the Cave 

 Hjiena, not only did not atti-act the attention of the workmen at the time, but it 

 remained unobserved for twenty-two years. Soon after quanying was resumed, in 

 March last, the removal of the remnant of the outer wall caused a portion of the dyke 

 to fall. Numerous bones were now so conspicuous amongst the earth and stones, 

 that the principal workmen soon collected several hundreds, consisting of teeth, jaws, 

 skulls, vertebrae, and poi-tious of horns, vrith a large qiiantity of unidentifiable bone- 

 debris. There is no probability that the so-called dyke formed originally portion of 

 a mass filling a cavern, great part of which was destroyed by the workmen twenty 

 years ago, for in the neighbourhood it was known that cave bones would fetch good 

 prices. In fact, the handwriting of the departed limestone was -y-isible on the breccia 

 sheet that had been so long exposed. Near the southern foot of the dj'ke is the 

 mouth of a small tunnel, with a stalagmitic floor ; its extent is not known. In the 

 southern wall of the quany are two large chambers, filled with the reddish earth 

 and limestone debris ; they are known to be connected, but it is not known whe- 

 ther they comnmnicate with the tunjiel ; it is exceedingly probable, however, that 

 they are aU parts of one considerable cavern. All the materials of the dyke im- 

 doubtedly fell, or were washed in from above ; giving a good example of what pro- 

 bably occurred at Orestone, near Plymouth, where observed phenomena compel the 

 belief that the fossil bones must in this way have found ingress to the cavern, 

 though lines of fissure are not always very distinct there. The owner had now 

 decided to explore the chambers and timnel himself; but although he had declined 

 to sell the right so to do, he had always given the author access, had promised to 

 enable him to note eveiy fact discovered, and he had also lent the exhibited speci- 

 mens. There is a gxeat field for exploration at Brixham. It is to be hoped that 

 quarrymen may not in futm-e be so blind to their own interests as to lay open a 

 dyke of osseous breccia without discovering that they have done so ; and that a 

 proprietor will not, as in a case within the author's knowledge, admit that he had 

 filled up a cavern, which he called "a large hole in the rock," by "throwing 

 twenty cai-tloads of mbbish into it." 



On the BeceM EncroacJiments of the Sea on the Shores of Torhay. 

 By W. Pengelly, F.G.S. 

 Hard Devonian limestones, fissile and jointed, formed, the author said, the two 

 projecting homs of Torbaj'. Sandstones and conglomerates foi-m the hollow of the 

 bay, and have been much worn away within the memoiy of man, especially at 

 Livermead, which is only preseiTed by continual engineering labour. The process 

 of erosion by the sea was explained by the author as something IDie a succession of 

 honej'combing, sometimes by insulation of portions of the cliffs. On the slates and 

 limestones the sea more slowly produced excavations, which storms enlarge. The 

 effects of the severe storm of October 1859 on the clifls, beach, roads, &c. of Torbay 

 were described in detail, and the importance of such storms as modem agents of 

 change was dwelt upon. 



On the Eelative Aye of the Pethei~win and Barnstaple Beds. 

 By W. Pengelly, F.O.S. 



In a paper on the Chronological and Geographical Distribution of the Devonian 

 Fossils of Devon and Cornwall*, read before this Section last year at Oxford, I 

 expressed the pro-visional opinion that there was not sufficient evidence to war- 

 rant the chi'onological separation of the Petherwin and Barnstaple beds. More 

 recently I have reconsidered the question, and have foimd reasons for changing my 

 opinion. 



* See ' Eeport' for 1860, p. 91. 



