Is the Microfilm Record Complete?

This past week, I was searching through the microfilm records of the Fourth Presbyterian Church in Philadelphia, Pennsylvania at the Brigham Young University, Harold B. Lee Library, Family History Library. The FamilySearch Catalog listing for these records is as follows;

Church records, 1800-1900 [Fourth Presbyterian]
Authors:
Fourth Presbyterian Church (Philadelphia, Pennsylvania) (Main Author)
Format:
Manuscript/Manuscript on Film
Language:
English
Publication:
Salt Lake City, Utah : Filmed by the Genealogical Society of Utah, 1968, 1972
Physical:
on 8 microfilm reels ; 35 mm.

 None of these records have been digitized, so it is back to the microfilm viewers. In this case, I am fortunate. The BYU Family History Library has ScanPro 2000s for viewing and copying the microfilms. The challenge is that I am looking for a specific range of dates. My Great-great-grandfather, William Linton, immigrated from Canada (originally from Northern Ireland) in about 1850. His wife and family came separately from New Brunswick to Philadelphia in 1851. The exact date is not recorded but the record shows that it was from the 2nd Quarter beginning in April.

I have yet to find when William Linton came to the United States. Unfortunately, he died in December of 1851 and was buried in the Fourth Presbyterian Church Burial Ground in Philadelphia. Part of my investigation is an attempt to determine when and where he was born in Northern Ireland. The family has recorded his birthdate only as 1801 in Ardstraw, Tyrone, Ireland but the birth date comes only from his death records. The family records and those on the FamilySearch.org Family Tree, show that William Linton's father was Samuel Linton, b. 1775 in County Down, Ireland. There are seven other Samuel Lintons in the Family Tree without birth or death information. Despite the family traditions, there are no sources supporting a line that somehow moves from Tyrone, Ireland to County Down, Ireland.

Here is the problem with the Fourth Presbyterian Church records in the FamilySearch Catalog.

Baptisms 1800-1819, 1834-1835 -- Communicants (members) -- Marriages 1800-1835, 1824-1838
Family History Library
United States & Canada Film
912992 Items 3 - 4

Baptisms 1800-1819, 1834 -- Communicants -- Marriages 1800-1835 (another filming)
Family History Library
United States & Canada Film
558299 Item 1

Communicants (members) -- Baptisms 1863-1880 -- Marriages 1863-1874, 1877-1880 -- Deaths 1880
Family History Library
United States & Canada Film
912992 Items 5 - 6

Communicants -- Baptisms 1863-1878 -- Marriages 1863-1874 (another filming, 1972)
Family History Library
United States & Canada Film
558476 Item 14

Communicants -- Baptisms 1878-1880 -- Marriages 1877-1880 -- Deaths 1880 (another filming)
Family History Library
United States & Canada Film
558477 Item 1

Communicants -- Baptisms 1880-1882, 1886-1887 -- Marriages 1881-1888
Family History Library
United States & Canada Film
912993 Item 1

Pastors -- Communicants -- Baptisms 1880-1887 -- Marriages 1881-1888 (another filming, 1972)
Family History Library
United States & Canada Film
558476 Item 13

Communicants -- Baptisms 1886-1900
Family History Library
United States & Canada Film
558477 Items 2 - 3

Communicants -- Baptisms 1886-1900 (another filming)
Family History Library
United States & Canada Film
912993 Items 2 - 3

Trustee minutes 1803-1817
Family History Library
United States & Canada Film
558292 Item 1

Trustee minutes 1803-1817 (another filming, 1972)
Family History Library
United States & Canada Film
912993 Item 7

Session minutes 1802-1834, 1841-1892
Family History Library
United States & Canada Film
558473 Items 1-3

Session minutes 1802-1834, 1841-1892 (another filming, 1972)
Family History Library
United States & Canada Film
912993 Items 4 - 6

If you look carefully at the dates covered by the records and focus on those records that might help find a person in 1851 or before, you will see that there are several gaps in the records. When did William Linton leave Canada for the United States? One limiting factor is the fact that his last child, John Selfridge Linton, was supposedly born in 1842 in New Brunswick, Canada. So the most reasonable time period was likely from 1842 to 1851. 

There are only two sets of these microfilmed records that cover that time period. Even though the titles to the records only mention certain time periods, if you were being careful about your research, you would pull all of these microfilms and check to make sure the cataloging data was correct and that there were not some later or earlier records stuck in that got missed in the cataloging process. So, I am going to have to look at every one of these records.

But the more important issue is whether or not the records are complete. Can I assume that I have made an adequate (reasonably exhaustive) search if I conclude that the information is not there? Well, I am just starting to gather records on this particular point and I will probably move to Canadian records as soon as I finish with the Church records. 

The point is important. You need to be carefully aware of the time periods involved in your research. Obviously, you also need to be liberal and check many years before and after the dates traditionally recorded for an individual, especially if the individual has no listed sources.