The evening was growing late, and there were still half a dozen miles of rough moorland between Ramna and Stromness. Over the braes of Borwick we travelled at a steady pace. We were light of heart, for we had had a successful expedition, as was proved not only by our dead falcon and the two seals' skins, but, more than all, by the great wealth that those seals' skins carried. Many were our conjectures as to the meaning of that great horde of silver we had discovered hidden in the sands of Skaill Bay. "I wonder how it all came there!" mused Robbie, and then he added, "D'ye ken what I think, lads?" "What think you, then, Robbie?" I asked. "Well," said he, "I just think it must have been cast there by some shipwreck in the olden time. D'ye mind, Hal, of the story of the wreck of yon Spanish ship on the Carrig-na-Spana?" "What! the San Miguel?" "Ay, maybe that was her name, I dinna ken. Well, if you mind, she struck on the reef there, and the skipper dropped all his treasure chests overboard, in mortal fear that the Orkney wreckers would rob him of them. I suppose he took his bearings, but for many a day the wreckers searched the waters, and never a thing did they find. Well, years and years after that the old skipper's son came to Orkney, and went straight to the spot where the treasure had been sunk and carried it all off to Spain." "But that explains nothing, Robbie," I argued. "However, we ken well enough that those Spanish ships were aye loaded with gold and precious stones. And then, d'ye not mind of hearing about the Spanish Armada ships that were wrecked on the Orkneys? Now, I wouldn't be surprised though the gear we have gotten was nothing else than the wreckage of an Armada ship. Even the skull that Willie found, maybe belonged to one of the soldier chaps that came to fight the English. But what is your opinion, Willie? You should know, for it was you who found the treasure." "Well, Ericson," said he wisely, "I just think it was most extraordinary to see the heaps of siller come out of the very sands of the seashore, and in such a desolate place; and beyond that, it was a most providential thing that the dog ran after yon wee rat. What most gets over me, though, is to think of the rat making its nest in the dead man's skull. Man! what a fright I had when the beast jumped out! As for how the siller came there, I canna just say; but, you mind, the dominie told us in the school that, lang syne, some of those viking lads used to cruise hereabout. Now, I'm thinking that it's just possible one of them had maybe left the siller for safety in the Kierfiold Cave where I--where we found it, and clean forgotten to go back for it; just as old Betsy Matthew forgot the guineas she hid under the floor in the heel of a stocking." "Ay, I dinna doubt it may be so, Willie," observed Rosson. "But then, what about the dead man's head?"