We have seen Palm leaf, paper and Bhūrja patra, the major materials that are used for writing manuscripts. These are other two materials that were used only in the north eastern part of the country. Sāñcīpāt and Tūlipāt are the materials.
The Agaru or aloe tree is called as Sāñcī in Assam and its bark is termed as Sāñcīpāt. This material is only popular in north eastern part of the country. Bāṇa Bhaṭṭa refers this materials in his work Harṣacarita.
अगरुवल्कलकल्पितसञ्चयानि च सुभाषिताभाञ्जि पुस्तकानि।
Here, he mentions that the leaves were Subhāṣitas were written, got pink colour due to the nature of aloe bark.
The Buddhist work āryamañjuśrimūla kalpa too mentions agaru bark as being used for writing yantras and mantras.
Many manuscripts in Sāñcīpāt have been discovered in Assam and preserved in Guwahati University Library, Narayana Handiqui Res. Institute, Guwahati, Chamaria Sarga and Kamarupa Anusandhana Samiti.
These manuscripts were dated as 15-16th CE. Manuscripts of Mahābhārata made of Sāñcī is preserved in Jaipur Maharaja’s collection.
Tūlīpāt is actually a paper made in assam. Some manuscripts of Rāmāyaṇa are found in the Guwahati University Library.