From South Wales Daily News - Monday 08 August 1887:

DIVING OPERATIONS ON THE NORTH WELSH COAST. SOME REMARKABLE DISCOVERIES. "A SUBMARINE FITTING-SHOP."
  During the present summer some very interesting and noteworthy operations have taken place on the coast of Anglesey with the object of recovering property from vessels which have been wrecked on the Coal Rock, one of the most dangerous of the many reefs with which Great Britain is begirt. The rock lies about three miles east of the North Skerries, and at low water spring tides its ragged head reaches within three feet of the surface. Its dimensions are small, and it rapidly sinks to about ten fathoms of water. Vessels which have struck upon this hidden monster have gone down bodily, and have never been seen again, only a few spars and cordage being visible, but the Drogheda Steam Packet Company's paddle steamer Lord Athlumney, which was wrecked thereon early in June, has since laid on the top of the rock, and is, therefore, only partly submerged. It was considered possible to save some portion of her cargo, so a contract was entered into with the Dundee Salvage Company for that purpose. After recovering a considerable number of wool packs, bales of cloth, dead cattle, eggs, etc, the company's divers were instructed to further explore the slopes of the rock, and the result has been in the highest degree interesting. Marine engines, steam winches, boilers, broken iron, propellers, shafting, anchors and chains were reported in all directions, one of the divers graphically describing the scene as resembling a burned-down marine fitting shop. The expectation of the salvors expanded as local rumour raked up memories of bar-silver, bullion, block-tin, and other valuables, stored for ages in this weird hiding-place. Further examination led to the finding of large quantities of copper plates, copper ingots, rolls of lead, and an entire cargo of tin-plates in boxes [from cargo of SS Fawn, lost a few months previously]. Many of these articles have been traced back and identified. The work was superintended by Mr T. N. Armit and his principal assistant, Mr Charles Lindsay, and these gentlemen concur in the belief that the rock could be so destroyed as to leave 16 feet of clear water at low tide. It is a matter of some surprise that the Government have not ere this taken steps to have such dangerous reefs as the Coal Rock undermined as far as reasonably practicable, and thus remove these horrid submarine channel vaults and wreck stores from British waters, especially upon important trade routes.