Consists of family business records of the Ribeiro de Avellar family pertaining to their plantation (fazenda) Pau Grande and its manor house in the rural parish of Paty do Alferes, Brazil. The family operated the plantation using enslaved laborers and first focused solely on sugarcane production, but later expanded to grow coffee and other foodstuffs. The extracts from account books, correspondence, and receipts found in this collection provide a detailed financial account of the operations of a large colonial sugar and coffee plantation in Brazil in the 19th century.

There are two bound volumes containing transcribed excerpts of financial accounts documenting the plantation's finances spanning the period from 1797 to 1810. These excerpts were created by Luiz Gomes Ribeiro, then manager of the plantation following the death of its original owner, Antônio Ribeiro de Avellar in 1798. Luiz Gomes Ribeiro was required to report on his management of the plantation to his mother-in-law, Antonia Maria da Conceição. There are also later correspondence and receipts related to the management of the plantation in the mid 19th century under the control of Joaquim Ribeiro de Avellar (1791-1863), the son of Antônio Ribeiro de Avellar and Antonia Maria da Conceição. These later materials consist of 144 letters to Joaquim Ribeiro de Avellar written by Domingos Alves da Silva Porto, manager of Avellar & Companhia, an agricultural export business in Rio de Janeiro, along with receipts pertaining to expenses involved with running the plantation and selling its products.