148 Geological Society. 



them all upwards or all downwards, or some upward and some 

 downward ? 



In Huel Trevaunance mine some of the veins on coming in contact 

 with others are thrown down j but one of the veins (a) on coming in 

 contact with the vein (/) is thrown upwards ; and the vein \b) on 

 coming in contact with the vein (/) is also thrown upwards, as is the 

 vein (/) on coming in contact with the vein (e). 



The author having thus " compared the general rules, which are so 

 frequently discussed, with facts," says, "Notwithstanding there are nu- 

 merous exceptions, it may be assumed that where across vein is found 

 to have heaved two or three lodes towards one hand, the miner will not 

 often be very far wrong if he excavate in the same direction to recover 

 a dislocated portion of a fourth}" and the author further observes, 

 that he shall not be surprised if a different rule be found to prevail in 

 the districts where tin abounds, from that which obtains in a copper 

 country. He next proceeds to combat the received opinion, that all 

 interruptions or intersections in mineral veins are the effects of dis- 

 turbances, and that the order of intersection of the various veins is 

 the index of their relative age. He then enters upon the inquiry 

 whether the phenomena of intersections and dislocations are expli- 

 cable on the assumption of motion, the principal results of which in- 

 quiry are given in the abstract of the paper which is contained in 

 the printed " Proceedings " of the Society. 



A Notice of a Submarine Forest in Cardigan Bay, by the Rev. James 

 Yates, M.A. F.G.S. and L.S. was afterwards read. 



This forest extends along the coast of Merionethshire and Cardi- 

 ganshire, being divided into two parts by the estuary of the river 

 Dovey, which separates those counties. It is bounded on the land 

 side by a sandy beach and a wall of shingles. Beyond this wall is a 

 tract of bog and marsh formed by streams of water which are partially 

 discharged by oozing through the sand and shingles. The author ar- 

 gues that, as the position of the wall is liable to change, it may have 

 inclosed the part which is now submarine, and that it is not necessary 

 to suppose a subsidence effected by subterranean agency. 



The remains of the forest are covered by a bed of peat, and are 

 distinguished by an abundance of Pholas Candida and Teredo navalis. 



Among the trees of which the forest consisted is the Pinus sylvestris, 

 or Scotch fir j and it is shown that this tree abounded anciently in 

 several northern counties of England. The natural order of Coni- 

 ferce may thus be traced from the period of the independent coal 

 formation to the middle of the seventeenth century, although the 

 Scotch fir is now excluded from the native Flora. 



The amentaceous wood presents matter for reflection, in consequence 

 of the perfect preservation of its vascular structure, while the con- 

 tents of the vessels are entirely dissipated. 



This tract is known to the Welsh under the name of Cantrev 

 Gwaelod, i. e. the Lowland Hundred. The author refers to the Triads 

 of Britain, and to other ancient Welsh testimonies, which prove that 

 it was submerged about A. D. 520, and ascribe the disaster to the 

 folly of " Seitheryn, the Drunkard, who in his drink let the Bea over 

 he Cantrev Gwaelod." 



