2 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



doubly thick seam was again met with, and on being followed 

 gradually assumed its normal thickness. 



No fossils have been noted in the "Wash-out" itself, the 

 vertical extension of which is unknown. 



Discussion. 



The Peesident considered that more particulars would have been 

 useful, and that the section should have been drawn to true scale. 

 He quoted cases in India where there was no thickening of the coal 

 at the edge ; the coal had apparently been washed away and 

 replaced by sandstone. It was difficult to understand why the coal 

 washed away should be redeposited at the edges of the stream. 



Prof. Green, with reference to the want of further particulars, 

 could only endorse what had been said. He spoke of the possible 

 existence of little ponds and lagoons where the cannel had been 

 forming. 



Prof. Hughes pointed out that the thicknesses did not give the ori- 

 ginal measurement of the coal. There was no mention of roots 

 going into the floor, which was described as uninterrupted. The 

 space had been filled up with less compressible material. 



Prof. J. F. Blake observed that this " dumb fault " was a portion 

 only of a much larger one. In this Mr. Coke had shown that 

 pressure from the sides had been brought to bear, which would 

 account for the thickening observed. Mr. Coke had suggested that 

 the " wash-out " was not due to ordinary denudation, but to an 

 original depression in an area of sinking. 



Prof. Lapwokth considered that such " dumb faults" as had been 

 investigated by himself were due to faulting and to distortion from 

 pressure. The edges of a " dumb fault " were slickensided. The 

 missing coal is to be found in the thickened seam. 



Mr. J. G. Wood alluded to a " dumb fault " described by the late 

 Mr. Buddie about 50 years ago. Subsequently a great contortion had 

 been discovered in near proximity to it, the coal being thrown into 

 an arch with a possible parting asunder. 



3. " On some Palaeozoic Ostracoda from North America, Wales, 

 and Ireland." By Prof. T. Kupert Jones, F.E.S., F.G.S. 



The following specimens were exhibited : — 



Eemains of a Pliosaur from the Oxford Clay of Peterborough, in 

 the collection of A. N. Leeds, Esq. ; the cast of a cervical vertebra 

 of Iguanodon from the Wealden of Hastings, in the possession of 

 P. Eufford, Esq. ; a cervical vertebra of a Plesiosaurian from the 

 Purbeck ; and a dorsal vertebra of Pelorosaurus {Ornithopsis) 

 Leedsi, in the collection of A. N. Leeds, Esq. ; exhibited in illus- 

 tration of the paper by R. Lydekker, Esq., F.G.S. 



Specimens of Palaeozoic Ostracoda, exhibited by Prof. T. Rupert 

 Jones, F.R.S., F.G.S. 



