190 Reports and Proceeduujs — Geological Society of London. 



and was felt over au area of about 12,000 square miles, its centre 

 coincitliiig with the village of Kniveton, near Ashbourne. The 

 shock consisted of two distinct parts, sepai'ated by an interval of 

 about three seconds, which coalesced, however, within a narrow 

 rectilinear band running centrally across the distui'bed area at right 

 angles to the longer axes of the isoseismal lines. The isacoustio 

 lines (or lines of equal sound-audibility) are very elongated curves, 

 distorted along the rectilinear band. The earthquake, it is con- 

 cluded, was caused by simultaneous slips within two detached foci 

 situated along a fault-service running from north 33° east to south 

 33° west, hading to the north-west, and passing close to the village 

 of Hognaston. The strongest after-shock occurred on May 3rd, its 

 focus lying along tlie same fault, for the most part between the two 

 foci of the principal earthquake, but much nearer the surface. 



Observations of the principal earthquake were made in many of 

 the mines near the epicentral district. The sound, in such cases, 

 was a much more prominent feature than the shock ; it appeared 

 to travel through the overlying strata, and in one pit in which 

 observations were made in four seams at different depths, it was 

 more distinctly audible in the lower than in the shallower seams. 



The principal earthquake was registered by an Omori horizontal 

 pendulum at Birmingham, by a Milne seismograph at Bidston (near 

 Birkenhead), and by a Weichert pendulum at Gottingen (502 miles 

 from the epicentre). The larger waves travelled with a velocity of 

 ■2'9 kilometres per second. 



III.— March 9th, 1904.— J. E. Marr, Sc.D., F.R.S., President, in the 

 Chair. The following communications were read : — 



1. " On the probable Occurrence of an Eocene Outlier off the 

 •Cornish Coast." By Clement Reid, Esq., F.R.S., F.L.S., F.G.S.^ 



An extensive deposit of subangular Chalk flints occurs near 

 Mai'azion, opposite a deep and wide valley which connects St. Ives 

 Bay and Mount's Bay. This valley, though containing at St. Erth 

 XiOwer Pliocene beds, is shown to be of much earlier date, and is 

 probably an Eocene river - valley. Eocene rivers seem to have 

 radiated from Dartmoor westward as well as eastwai'd. The flint- 

 and-chert gi'avel corresponds closely with the Eocene gravel of 

 Haldon, and is apparently derived from a deposit under the sea off 

 St, Michael's Moinit. Continuing the direction of the Eocene valley 

 seaward, the isolated mass of phonolite of the Wolf Rock is met 

 with. The evidence suggests that, underlying the western part 

 of the English Channel, an Eocene basin may occur comparable in 

 importance with that of Hampshire. 



2. " The Valley of the Teign." By Alfred John Jukes-Browne, 

 Esq., B.A., F.G.S. 



The Teign Valley is one of the most remarkable in the British 

 Islands, because it is not a transverse valley pi'eserving a general 

 direction in spite of opposing ridges, nor is it a longitudinal valley 

 ' Couimuuicated by peiiuissiou of the Director of H.M. Geological Survey. 



