On October 12, 1932, Mrs. Isabel Dillman purchased a portion of land in Karnes County in the E.R. Cosby Karnes County 300 Acre Lease Pool. The certificate starts thusly:

"This certifies that Mrs. Isabel Dillman is the owner of a 1/3000th interest in and to 300 acres oil and gas leases in Karnes County, Texas, described below, and is entitled to his (or her) prorata share of an sale of any properties comprising the E.R. Cosby - Karnes County - 300 Acre Lease Pool being the 7/8th oil and gas leases on THIRTEEN tracts of land comprising 300 acres, as described and of record in Deed Records of Karnes County, Texas..."

In the 1930 census, there was an Isabel Dillman (wife of J. Alex Dillman) living in Milwaukee, Wisconsin (Disctricts 1-250). No record if this is the same person.

In March of 1927, E.R. Cosby is listed as a defendant in a lawsuit regarding the cancellation of a mineral lease in Pottawatomie County in Oklahoma. Source: Hearn vs. Blakeney & Ambrister

You can view the lease certificate by clicking on the thumbnails below. The images are quite large and will open in a new window.