I returned to my book — Bewick's History of British Birds:th

I returned to my book — Bewick's History of British Birds:the letter press thereof I cared little for,generally speaking; and yet there were certain introductory pages that,child as I was,I could not pass quite as a blank.They were those which treat of the haunts of sea-fowl; of 'the solitary rocks and promontories' by them only inhabited; of the coast of Norway,studded with isles from its southern extremity,the Lindeness,or Naze,to the North Cape —
以上是《简爱》英文版中的片段,读罢有些不懂之处,
1thereof是什么意思?什么用法?没有thereof这个句子似乎也说得通,加与不加有区别吗?
2、I could not pass quite as a blank这句不理解,quite是咋回事?as a blank是咋回事?
3、They were those which treat of treat of是短语吗?怎么每句后面都有of?
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