▁N ort he astern ▁Brazil ian ▁dialect . ▁Mar anh ão ▁is ▁described ▁in ▁books ▁such ▁as ▁The ▁Land ▁of ▁the ▁Pal m ▁Tre es ▁by ▁Gon ç al ves ▁D ias ▁and ▁Casa ▁de ▁P ens ão ▁by ▁Al u ís io ▁A ze ved o . ▁ ▁The ▁d unes ▁of ▁Len ç ó is ▁are ▁an ▁important ▁area ▁of ▁environmental ▁pres ervation . ▁Also ▁of ▁interest ▁is ▁the ▁state ▁capital ▁of ▁São ▁Lu ís , ▁designated ▁a ▁Un es co ▁World ▁Heritage ▁Site . ▁Another ▁important ▁conservation ▁area ▁is ▁the ▁Par na í ba ▁River ▁delta , ▁between ▁the ▁states ▁of ▁Mar anh ão ▁and ▁Pia u í , ▁with ▁its ▁l ago ons , ▁desert ▁d unes ▁and ▁desert ed ▁be aches ▁or ▁islands , ▁such ▁as ▁the ▁C aju ▁island , ▁which ▁sh el ters ▁rare ▁birds . ▁ ▁Geography ▁ ▁The ▁northern ▁portion ▁of ▁the ▁state ▁is ▁a ▁heavily ▁for ested ▁plain ▁travers ed ▁by ▁numerous ▁rivers , ▁occupied ▁by ▁the ▁eastern ▁extension ▁of ▁the ▁tropical ▁mo ist ▁for ests ▁of ▁Ama z onia . ▁The ▁T oc ant ins - A rag ua ia - Mar anh ão ▁mo ist ▁for ests ▁occup y ▁the ▁north western ▁portion ▁of ▁the ▁state , ▁extending ▁from ▁the ▁P ind ar é ▁River ▁west ▁into ▁neighbor ing ▁Par á ▁state . ▁The ▁north - central ▁and ▁n ort he astern ▁portion ▁of ▁the ▁state , ▁extending ▁east ward ▁into ▁northern ▁Pia u í , ▁is ▁home ▁to ▁the ▁Mar