Arched itself into・・の意味
以下の文書の意味がよく解りません。大意でも結構ですのでアドバイスよろしくお願いします。
I was in time to see the bank they had undercut arching itself into ridges. I had seen the waves in the strata along the bank, made by old tremors; but those were only ripples. It arched itself into low hills now, and they suddenly came towards us. The whole bog was moving.
・アイルランドの湿原(bog)の周辺の土手がピートを採取するため開発されて、土手に沿って横に掘削されている。
・数ヶ月雨が続き、このあと湿原が決壊して水が周囲に流れ出すという状態です。
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これに続く文章
With the weight of years of rain and those last three months it was coming over the lower lands,
and rising higher and higher as it came. For as far as I could see, left or right, it was ripping and waving.
最初のブロックのIt arched itself into low hills now, and they suddenly came towards us. のItとtheyが何なのかが解りません。よろしくお願いします。
お礼
お二方とも、ご回答、ありがとうございます。 callが含まれていたなんて盲点でした。 もっと勉強します！ ありがとうございました☆