474 Geological Society :— 



in width, and running along the northerly edge of Dartmoor, along 

 the line of junction of the granite and the altered carbonaceous 

 rocks. The length of the area affected by the earthquake is about 

 21 miles, from Crediton on the east to the Fox and Hounds Inn, 

 on the Tavistock Road, about 7 miles ft-om Okehampton. The 

 shock seems to have taken a direction from east to west, to have 

 occurred about 8 o'clock in the evening, and to have lasted, where 

 most severe, about 15 seconds. 



3. " Notice of certain Veins of Granite in the Carbonaceous 

 Rocks on the North and East of Dartmoor." By G. Wareing 

 Ormerod, Esq., F.G.S. 



The following localities are quoted by the author as affording 

 more or less distinct evidence of granitic veins traversing the carbo- 

 naceous rocks. Near Meldon, 2 miles S.W. of Okehampton ; 

 Cocktree Moor; in the Gorge of the Teign after leaving Hunts 

 Tor ; the most northerly point of Whyddon Park, and the hill-side 

 nearly opposite ; on the hill-side above the Logan Stone ; near 

 Westerly Tor ; on Sharpy Tor ; on the road from Cranbrook Castle 

 to Fingle Bridge ; and the road down the hill to the west of Cran- 

 brook Farm. 



4. " On the Structure of some of the Siliceous Nodules of the 

 Chalk." By N. T. Wetherell, Esq. Communicated by the President. 



The author first described several specimens of the peculiar 

 banded flints found in the chalk and in gravel, and of which he had 

 made a large collection during several years. They usually exhibit 

 a central longitudinal axis or narrow stem, crossed on its middle third 

 by numerous short parallel stripes of alternately light and dark flint, 

 and frequently terminated at each extremity by an irregular mass of 

 flint, often clouded or grey. The axis occurs sometimes solated, 

 sometimes covered with a thin coating of grey flint only, and some- 

 times associated with only a few cross stripes of the banded structure. 

 In some instances the handed flint has for its axis a sponge, or frag- 

 ments of sponge. 



The author had not found in the banded flint any spongy tissue 

 peculiar to it ; in some instances, however, a silicified sponge 

 appears to have been traversed by alternate lines of the light and 

 dark colour analogous to those of the banded flints. In some 

 instances a concentric arrangement of light and dark layers of flint 

 occurs around the two ends of an axis, or around isolated nuclei. 

 Mr. Wetherell regarded this banded appearance in the flint as not 

 being due to an organic structure, but to have originated in a peculiar 

 arrangement of the siliceous matter around organic bodies, frequently 

 long and stem-like, such as those of the Graphularia which supplied 

 so many axial nuclei to the concretions in the London Clay. 



November 17. — L. Horner, Esq., V.P., in the Chair. 

 The following communications were read :- — 

 1. " On some Fossils fi-om South Africa." By C. W. Stow, Esq. 

 In a letter to the Assistant-Secretary. 



At the close of 1850 Mr. Stow and his party fell back into the 



I 



