わからない箇所について教えてください。
"The valley is sharp, and Altesa extends about a quarter of the way up it from the sea. The buildings of the town are huddled together between shoulders of land that rise on either side. From the very top of the town, the coast is only an hour’s walk away, if you’re young. You can go the whole way in bare feet in that time. The beaches are rocky, and there are inlets and coves hidden away which can be reached only by the cliffs, or by scrambling around promontories. In summer, the sea from the cliffs is hugely blue, like deeply fired ceramic, but glittering with motion. Gentle Mediterranean currents guide the shoals of fishes, and underwater the rocks are furred with weed and patterned with constantly moving bands of cool light."
Guy BurtのThe Dandelion Clockからの英文です。
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Altesa extends about a quarter of the way up it from the sea.の個所について。
Altesaというのは地名だと思うのですが、about a quarter of the way up it from the sea.のところがわかりません。itはThe valleyですか？about a quarter（4分の1？） of the wayとは？
The buildings of the town are huddled together between shoulders of land that rise on either side. の個所について。
shoulders of land that rise on either side.のところがよくわかりません。どんな感じなのでしょうか？
教えてください。お願いします。
