In 1277 Edward invaded Wales, and was greatly assisted by David, who knew the country and the people, and was able to foment jealousies among the Welsh chieftains, and cripple Llewelyn in his resistance to the advance of the invader, by detaching them from his allegiance. Owen the Red from his prison contrived to send to Edward his best wishes for his success. Llewelyn was now obliged to take refuge in Snowdon, and was forced to come to terms with Edward, and by these terms he was compelled to release Owen. After this we hear little more of this red-haired fox, and it is probable that his long captivity had broken his health. Now the false and fickle David deserted Edward, and went over to the side of Llewelyn, actuated, not by patriotism, but by self-interest. In 1282 King Edward again invaded Wales, but his advance was checked at Conway. He accordingly sent a fleet to effect the subjugation of Anglesey, and to form that a base for operations against Llewelyn in Snowdon. Having succeeded in this, Edward exclaimed exultantly, “Now I have plucked the finest feather out of Llewelyn’s tail.” Llewelyn, hard pressed in Snowdon, left that stronghold to be defended by David, whilst he hastened south to rally the Welsh under the prince of Dynevor. He fell into an ambush, as has been already related, and was killed. David was captured, and hanged, drawn, and quartered. Another prisoner detained in Dolbadarn was David Gam of Brecon, who tried to assassinate Owen Glyndwr. But about him more when we come to Machynlleth. To understand the topography of the Snowdon district we must conceive of Snowdon itself as shaped much like a star-fish with the radiating arms curved, and little lakes lying in the hollows between the ridges. The entire mass, however, forms a rude triangle with its base at Llyn Dinas and Llyn Gwynant and the pass of Bwlch-y-Gwyddel, the neck that attaches Snowdon to the stately mountain mass of Moel Siabod. North of Llyn Padarn and Llanberis is again a great mountain bulk. The geology of Snowdon is too complicated for the unscientific eye to understand and unravel, but broadly it may be described as eruptive matter breaking through the Cambrian slates. These slates are the best in England, though their purple tinge is unpleasant to the eye, and the silvery grey is far more grateful. The slate quarries find employment for armies of workmen, but are detrimental to the beauty of the scenery, the mountain-sides being sliced and hacked and hewn into, and over the hideous piles of débris it will take thousands of years for the grass to grow. Even the uninitiated eye will soon be able to detect the traces of glacial action in scored rocks as the great ice rivers moved over them, scratching them with the stones embodied in the frozen stream, in the fragmentary moraines, and in the eratic blocks.