The Church Records index covers about one-quarter of the church records held by the Connecticut State Library, mostly Congregational. There is no specific cutoff date for the index; most entries date before 1850, but there are some to the early 1900s. It does not include Catholic or Jewish records. 
The List of the Church Records we hold can be found in our Digital Collections. If there is a notation 'SLI' next to the list of Churches, the records appear in our index.
Each slip gives a complete abstract of an event, e.g., a baptism, marriage, or burial. At the bottom of the slip is a citation to the original record from which the fact was taken, including town, church, volume, and page. In most cases, there is no more information in the original record than what is shown in the transcription, so that unless there is a question regarding the accuracy of the transcription, it is not necessary to go to the original record. The reference in the index is to the original record which for the most part is on microfilm and available through a Place search in the FamilySearch catalog.