Book 1 of the Zygradon Chronicles:
When Ceera woke up, Mrillis turned most of his attention to entertaining the little girl and keeping her quiet. Besides, the talk of numbers and provisions and arrangements for sailing from Wynystrys to Moerta bored him. He had one question, and asked it as soon as the visitors left and Le'esha called the children out of their hiding place.
"Why can't they just walk to Moerta?" he asked, on the heels of Le'esha commending the children for being so good.
"Walk?" The Queen of Snows blinked, visibly caught off balance, and sat down in her chair. Then she laughed. "You mean the tunnels that we use to travel between the enclaves? Oh, my dear, do you know how far it is from the shores of Lygroes to the shores of Moerta?"
"Magic makes the distance shorter," Mrillis said. Now he was confused. He knew that if he rode a horse, it would take him one whole moon to travel from Wynystrys, on the western shore of Lygroes, to the Stronghold, on the far northeastern tip of the continent. Walking the tunnel from the Stronghold to the island, however, took less than a day. He had never gone into the tunnel, but he had stood at the barred door of the entrance. He knew the tingling in his fingertips and the whispering in the back of his mind was his imbrose, reacting to magic at work.
"Yes, magic does make the distance shorter. And only those of Rey'kil blood, with strong imbrose, can use the tunnels. There is no tunnel under the sea, reaching to Moerta."
"We could build one."
"Hmm, yes, but how much power do you think it would take to dig a tunnel, much less keep the weight of all that water and stone from crushing it?" Le'esha sighed and smiled and reached out her arms to the children.
Ceera, who was sleepy again, crept up into her lap. Mrillis leaned into the warmth of her arm around him and rested his elbows on the arm of her chair.
"I don't know," he admitted, after thinking a long while.
"That is knowledge you must grow into. Just as you will grow into whatever talent the Estall has given you."